From 9f00585d9f056414419d50e1b2ceeaf700354ffc Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 24 Sep 2024 19:34:13 +0900
Subject: [PATCH 01/45] 217 / Contains Duplicate / Easy / 8m

---
 alexgoni/217_Contains_Duplicate.js | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 alexgoni/217_Contains_Duplicate.js

diff --git a/alexgoni/217_Contains_Duplicate.js b/alexgoni/217_Contains_Duplicate.js
new file mode 100644
index 0000000..10404cb
--- /dev/null
+++ b/alexgoni/217_Contains_Duplicate.js
@@ -0,0 +1,14 @@
+/**
+ * @param {number[]} nums
+ * @return {boolean}
+ */
+var containsDuplicate = function (nums) {
+  const numberDict = {};
+
+  for (const num of nums) {
+    if (numberDict[num] === undefined) numberDict[num] = true;
+    else return true;
+  }
+
+  return false;
+};

From c3c0a1f75f48ae1da8293999780d36ef62bc829a Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 24 Sep 2024 19:42:08 +0900
Subject: [PATCH 02/45] 268 / Missing Number / Easy / 4m

---
 alexgoni/268_Missing_Number.js | 11 +++++++++++
 1 file changed, 11 insertions(+)
 create mode 100644 alexgoni/268_Missing_Number.js

diff --git a/alexgoni/268_Missing_Number.js b/alexgoni/268_Missing_Number.js
new file mode 100644
index 0000000..6d4dc1f
--- /dev/null
+++ b/alexgoni/268_Missing_Number.js
@@ -0,0 +1,11 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var missingNumber = function (nums) {
+  const n = nums.length;
+  const sum = (n * (n + 1)) / 2;
+  const missingSum = nums.reduce((a, c) => a + c, 0);
+
+  return sum - missingSum;
+};

From e1bf0a76c85956e7693d7d07d2cc816b996c59b2 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 24 Sep 2024 20:31:41 +0900
Subject: [PATCH 03/45] Meeting Schedule / Easy / 10m

---
 alexgoni/Meeting_Schedule.js | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 alexgoni/Meeting_Schedule.js

diff --git a/alexgoni/Meeting_Schedule.js b/alexgoni/Meeting_Schedule.js
new file mode 100644
index 0000000..a32672f
--- /dev/null
+++ b/alexgoni/Meeting_Schedule.js
@@ -0,0 +1,25 @@
+/**
+ * Definition of Interval:
+ * class Interval {
+ *   constructor(start, end) {
+ *     this.start = start;
+ *     this.end = end;
+ *   }
+ * }
+ */
+
+class Solution {
+  /**
+   * @param {Interval[]} intervals
+   * @returns {boolean}
+   */
+  canAttendMeetings(intervals) {
+    intervals.sort((a, b) => a.start - b.start);
+
+    for (let i = 0; i < intervals.length - 1; i++) {
+      if (intervals[i + 1].start < intervals[i].end) return false;
+    }
+
+    return true;
+  }
+}

From 130847cc4ec435f83fd6ad8e1de7383419056438 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 24 Sep 2024 22:02:26 +0900
Subject: [PATCH 04/45] 121 / Best Time to Buy and Sell Stock / Easy

---
 .../121_Best_Time_to_Buy_and_Sell_Stock.js    | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 alexgoni/121_Best_Time_to_Buy_and_Sell_Stock.js

diff --git a/alexgoni/121_Best_Time_to_Buy_and_Sell_Stock.js b/alexgoni/121_Best_Time_to_Buy_and_Sell_Stock.js
new file mode 100644
index 0000000..a6b11da
--- /dev/null
+++ b/alexgoni/121_Best_Time_to_Buy_and_Sell_Stock.js
@@ -0,0 +1,19 @@
+// 😢
+
+/**
+ * @param {number[]} prices
+ * @return {number}
+ */
+var maxProfit = function (prices) {
+  let minPrice = Number.POSITIVE_INFINITY;
+  let maxProfit = 0;
+
+  for (const price of prices) {
+    if (minPrice > price) minPrice = price;
+
+    const profit = price - minPrice;
+    if (profit > maxProfit) maxProfit = profit;
+  }
+
+  return maxProfit;
+};

From 83256b25f6faf48279ba58b52d59235412cb0200 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 24 Sep 2024 22:46:42 +0900
Subject: [PATCH 05/45] 15 / 3Sum / Medium

---
 alexgoni/15_3Sum.js | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 alexgoni/15_3Sum.js

diff --git a/alexgoni/15_3Sum.js b/alexgoni/15_3Sum.js
new file mode 100644
index 0000000..51a6125
--- /dev/null
+++ b/alexgoni/15_3Sum.js
@@ -0,0 +1,43 @@
+// 😢
+
+/**
+ * @param {number[]} nums
+ * @return {number[][]}
+ */
+var threeSum = function (nums) {
+  const result = [];
+
+  nums.sort((a, b) => a - b);
+
+  for (let i = 0; i < nums.length - 2; i++) {
+    if (i > 0 && nums[i] === nums[i - 1]) continue;
+
+    const fixed = nums[i];
+    let left = i + 1;
+    let right = nums.length - 1;
+
+    while (left < right) {
+      const sum = fixed + nums[left] + nums[right];
+
+      if (sum === 0) {
+        result.push([fixed, nums[left], nums[right]]);
+
+        while (left < right && nums[left] === nums[left + 1]) left++;
+        while (left < right && nums[right] === nums[right - 1]) right--;
+
+        left++;
+        right--;
+      } else if (sum > 0) {
+        right--;
+      } else {
+        left++;
+      }
+    }
+  }
+
+  return result;
+};
+
+console.log(threeSum([0, 0, 0, 0]));
+
+// -4, -1, -1 ,0 ,1, 2

From 8810c0d9ab0128bb948dd28ab32bfbd720046ff8 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Thu, 3 Oct 2024 14:32:31 +0900
Subject: [PATCH 06/45] 242 / Valid Anagram / Easy / 7m

---
 alexgoni/242_Valid_Anagram.js | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 alexgoni/242_Valid_Anagram.js

diff --git a/alexgoni/242_Valid_Anagram.js b/alexgoni/242_Valid_Anagram.js
new file mode 100644
index 0000000..bb4cee8
--- /dev/null
+++ b/alexgoni/242_Valid_Anagram.js
@@ -0,0 +1,29 @@
+/**
+ * @param {string} s
+ * @param {string} t
+ * @return {boolean}
+ */
+var isAnagram = function (s, t) {
+  const frequencyCounter1 = {};
+  const frequencyCounter2 = {};
+
+  [...s].forEach((str) => {
+    frequencyCounter1[str] = (frequencyCounter1[str] || 0) + 1;
+  });
+
+  [...t].forEach((str) => {
+    frequencyCounter2[str] = (frequencyCounter2[str] || 0) + 1;
+  });
+
+  if (
+    Object.keys(frequencyCounter1).length !==
+    Object.keys(frequencyCounter2).length
+  )
+    return false;
+
+  for (const key in frequencyCounter1) {
+    if (frequencyCounter1[key] !== frequencyCounter2[key]) return false;
+  }
+
+  return true;
+};

From 427e43611700cb0a01cdbb6e2df3a045003934bf Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Fri, 4 Oct 2024 10:22:23 +0900
Subject: [PATCH 07/45] 238 / Product of Array Except Self / Medium

---
 alexgoni/238_Product_of_Array_Except_Self.js | 23 ++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 alexgoni/238_Product_of_Array_Except_Self.js

diff --git a/alexgoni/238_Product_of_Array_Except_Self.js b/alexgoni/238_Product_of_Array_Except_Self.js
new file mode 100644
index 0000000..842aa70
--- /dev/null
+++ b/alexgoni/238_Product_of_Array_Except_Self.js
@@ -0,0 +1,23 @@
+// 😢
+
+/**
+ * @param {number[]} nums
+ * @return {number[]}
+ */
+var productExceptSelf = function (nums) {
+  const result = Array.from({ length: nums.length }, () => 1);
+
+  let leftProduct = 1;
+  for (let i = 0; i < nums.length; i++) {
+    result[i] = leftProduct;
+    leftProduct *= nums[i];
+  }
+
+  let rightProduct = 1;
+  for (let i = nums.length - 1; i >= 0; i--) {
+    result[i] *= rightProduct;
+    rightProduct *= nums[i];
+  }
+
+  return result;
+};

From a8ae2fcf56d9f30326cf1ccfc77a4c1ffa3bdb7d Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Fri, 4 Oct 2024 13:55:31 +0900
Subject: [PATCH 08/45] 191 / Number of 1 Bits / Easy / 3m

---
 alexgoni/191_Number_of_1_Bits.js | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
 create mode 100644 alexgoni/191_Number_of_1_Bits.js

diff --git a/alexgoni/191_Number_of_1_Bits.js b/alexgoni/191_Number_of_1_Bits.js
new file mode 100644
index 0000000..a94726c
--- /dev/null
+++ b/alexgoni/191_Number_of_1_Bits.js
@@ -0,0 +1,15 @@
+/**
+ * @param {number} n
+ * @return {number}
+ */
+var hammingWeight = function (n) {
+  let result = 0;
+
+  [...n.toString(2)].forEach((each) => {
+    if (each === "1") result++;
+  });
+
+  return result;
+};
+
+console.log(hammingWeight(2147483645));

From 96461d9592509ec84158ac22785f99e21b4c7231 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Sat, 5 Oct 2024 00:20:20 +0900
Subject: [PATCH 09/45] 100 / Same Tree / Easy / 30m

---
 alexgoni/100_Same_Tree.js | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 alexgoni/100_Same_Tree.js

diff --git a/alexgoni/100_Same_Tree.js b/alexgoni/100_Same_Tree.js
new file mode 100644
index 0000000..133db63
--- /dev/null
+++ b/alexgoni/100_Same_Tree.js
@@ -0,0 +1,39 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} p
+ * @param {TreeNode} q
+ * @return {boolean}
+ */
+var isSameTree = function (p, q) {
+  const bfs = (start) => {
+    const result = [];
+    const queue = [start];
+
+    while (queue.length > 0) {
+      const current = queue.shift();
+
+      if (current === null) {
+        result.push(null);
+        continue;
+      } else result.push(current.val);
+
+      if (current.left) queue.push(current.left);
+      if (!current.left && current.right) queue.push(null);
+      if (current.right) queue.push(current.right);
+    }
+
+    return result;
+  };
+
+  const pArr = bfs(p);
+  const qArr = bfs(q);
+
+  return JSON.stringify(pArr) === JSON.stringify(qArr);
+};

From 169db8c346f989f1d6e09a06adaa22fc6581f94c Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Sat, 5 Oct 2024 13:43:48 +0900
Subject: [PATCH 10/45] 746 / Min Cost Climbing Stairs / Easy

---
 alexgoni/15_3Sum.js                      |  4 ----
 alexgoni/191_Number_of_1_Bits.js         |  2 --
 alexgoni/746_Min_Cost_Climbing_Stairs.js | 23 +++++++++++++++++++++++
 3 files changed, 23 insertions(+), 6 deletions(-)
 create mode 100644 alexgoni/746_Min_Cost_Climbing_Stairs.js

diff --git a/alexgoni/15_3Sum.js b/alexgoni/15_3Sum.js
index 51a6125..88df475 100644
--- a/alexgoni/15_3Sum.js
+++ b/alexgoni/15_3Sum.js
@@ -37,7 +37,3 @@ var threeSum = function (nums) {
 
   return result;
 };
-
-console.log(threeSum([0, 0, 0, 0]));
-
-// -4, -1, -1 ,0 ,1, 2
diff --git a/alexgoni/191_Number_of_1_Bits.js b/alexgoni/191_Number_of_1_Bits.js
index a94726c..f63c4ab 100644
--- a/alexgoni/191_Number_of_1_Bits.js
+++ b/alexgoni/191_Number_of_1_Bits.js
@@ -11,5 +11,3 @@ var hammingWeight = function (n) {
 
   return result;
 };
-
-console.log(hammingWeight(2147483645));
diff --git a/alexgoni/746_Min_Cost_Climbing_Stairs.js b/alexgoni/746_Min_Cost_Climbing_Stairs.js
new file mode 100644
index 0000000..772cb2d
--- /dev/null
+++ b/alexgoni/746_Min_Cost_Climbing_Stairs.js
@@ -0,0 +1,23 @@
+// 😢
+
+/**
+ * @param {number[]} cost
+ * @return {number}
+ */
+var minCostClimbingStairs = function (cost) {
+  const stairMinCost = Array.from({ length: cost.length }, () => 0);
+
+  stairMinCost[0] = cost[0];
+  stairMinCost[1] = cost[1];
+
+  for (let i = 2; i < cost.length; i++) {
+    if (stairMinCost[i - 1] >= stairMinCost[i - 2]) {
+      stairMinCost[i] = stairMinCost[i - 2] + cost[i];
+    } else stairMinCost[i] = stairMinCost[i - 1] + cost[i];
+  }
+
+  return Math.min(
+    stairMinCost[stairMinCost.length - 1],
+    stairMinCost[stairMinCost.length - 2]
+  );
+};

From 2beb97d606c929263121c75baf6d582e30702f7f Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Sun, 6 Oct 2024 13:34:10 +0900
Subject: [PATCH 11/45] 190 / Reverse Bits / Easy / 13m

---
 alexgoni/190_Reverse_Bits.js | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
 create mode 100644 alexgoni/190_Reverse_Bits.js

diff --git a/alexgoni/190_Reverse_Bits.js b/alexgoni/190_Reverse_Bits.js
new file mode 100644
index 0000000..09b09bf
--- /dev/null
+++ b/alexgoni/190_Reverse_Bits.js
@@ -0,0 +1,16 @@
+/**
+ * @param {number} n - a positive integer
+ * @return {number} - a positive integer
+ */
+var reverseBits = function (n) {
+  let bitsOf32 = "";
+  const binaryStr = n.toString(2);
+
+  for (let i = 0; i < 32 - binaryStr.length; i++) {
+    bitsOf32 += "0";
+  }
+  bitsOf32 += binaryStr;
+
+  const reversedBitsOf32 = [...bitsOf32].reverse().join("");
+  return parseInt(reversedBitsOf32, 2);
+};

From 14f6422de74078ef48dea84c87b20e5fd4ada708 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Mon, 7 Oct 2024 09:22:33 +0900
Subject: [PATCH 12/45] 125 / Valid Palindrome / Easy / 4m

---
 alexgoni/125_Valid_Palindrome.js | 12 ++++++++++++
 1 file changed, 12 insertions(+)
 create mode 100644 alexgoni/125_Valid_Palindrome.js

diff --git a/alexgoni/125_Valid_Palindrome.js b/alexgoni/125_Valid_Palindrome.js
new file mode 100644
index 0000000..dd6bb0b
--- /dev/null
+++ b/alexgoni/125_Valid_Palindrome.js
@@ -0,0 +1,12 @@
+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+var isPalindrome = function (s) {
+  let newStr = s.toLowerCase();
+  newStr = newStr.replace(/[^a-z0-9]/g, "");
+
+  const reverseStr = [...newStr].reverse().join("");
+
+  return newStr === reverseStr;
+};

From 85daeb7f20639e3511b30bab9797a47385953fcd Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 8 Oct 2024 21:09:55 +0900
Subject: [PATCH 13/45] 206 / Reverse Linked List / Easy / 24m

---
 alexgoni/206_Reverse_Linked_List.js | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 alexgoni/206_Reverse_Linked_List.js

diff --git a/alexgoni/206_Reverse_Linked_List.js b/alexgoni/206_Reverse_Linked_List.js
new file mode 100644
index 0000000..a570969
--- /dev/null
+++ b/alexgoni/206_Reverse_Linked_List.js
@@ -0,0 +1,25 @@
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val, next) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.next = (next===undefined ? null : next)
+ * }
+ */
+/**
+ * @param {ListNode} head
+ * @return {ListNode}
+ */
+var reverseList = function (head) {
+  let current = head;
+  let prev = null;
+  let next;
+
+  while (current) {
+    next = current.next;
+    current.next = prev;
+    prev = current;
+    current = next;
+  }
+
+  return prev;
+};

From c95b2b5e8e08ffbc050fc6829c626fdb2ac68afa Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 8 Oct 2024 23:53:56 +0900
Subject: [PATCH 14/45] 49 / Group Anagrams / Medium / 30m

---
 alexgoni/49_Group_Anagrams.js | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 alexgoni/49_Group_Anagrams.js

diff --git a/alexgoni/49_Group_Anagrams.js b/alexgoni/49_Group_Anagrams.js
new file mode 100644
index 0000000..c8de8c0
--- /dev/null
+++ b/alexgoni/49_Group_Anagrams.js
@@ -0,0 +1,19 @@
+/**
+ * @param {string[]} strs
+ * @return {string[][]}
+ */
+var groupAnagrams = function (strs) {
+  const dict = {};
+
+  for (const str of strs) {
+    const sortedStr = [...str].sort().join("");
+
+    if (dict[sortedStr]) {
+      dict[sortedStr].push(str);
+    } else {
+      dict[sortedStr] = [str];
+    }
+  }
+
+  return Object.values(dict);
+};

From aa029fb14d7cea9528dab38aa5da50a896c4c364 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Wed, 9 Oct 2024 10:51:01 +0900
Subject: [PATCH 15/45] 322 / Coin Change / Medium

---
 alexgoni/322_Coin_Change.js | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 alexgoni/322_Coin_Change.js

diff --git a/alexgoni/322_Coin_Change.js b/alexgoni/322_Coin_Change.js
new file mode 100644
index 0000000..2c2f0d2
--- /dev/null
+++ b/alexgoni/322_Coin_Change.js
@@ -0,0 +1,21 @@
+// 😢
+
+/**
+ * @param {number[]} coins
+ * @param {number} amount
+ * @return {number}
+ */
+var coinChange = function (coins, amount) {
+  const dp = Array(amount + 1).fill(Infinity);
+  dp[0] = 0;
+
+  for (let i = 1; i <= amount; i++) {
+    for (let coin of coins) {
+      if (i >= coin) {
+        dp[i] = Math.min(dp[i], dp[i - coin] + 1);
+      }
+    }
+  }
+
+  return dp[amount] === Infinity ? -1 : dp[amount];
+};

From 8b0f8bb1675f37874c059c9e63cf46177bf2bfc7 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Wed, 16 Oct 2024 09:03:52 +0900
Subject: [PATCH 16/45] 1 / Two Sum / Easy / 4m

---
 alexgoni/1_Two_Sum.js | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 alexgoni/1_Two_Sum.js

diff --git a/alexgoni/1_Two_Sum.js b/alexgoni/1_Two_Sum.js
new file mode 100644
index 0000000..df8b5a5
--- /dev/null
+++ b/alexgoni/1_Two_Sum.js
@@ -0,0 +1,30 @@
+// /**
+//  * @param {number[]} nums
+//  * @param {number} target
+//  * @return {number[]}
+//  */
+// var twoSum = function (nums, target) {
+//   for (let i = 0; i < nums.length - 1; i++) {
+//     for (let j = i + 1; j < nums.length; j++) {
+//       const sum = nums[i] + nums[j];
+
+//       if (sum === target) return [i, j];
+//     }
+//   }
+// };
+
+/**
+ * @param {number[]} nums
+ * @param {number} target
+ * @return {number[]}
+ */
+var twoSum = function (nums, target) {
+  const obj = {};
+
+  for (let i = 0; i < nums.length; i++) {
+    const value = nums[i];
+    if (target - value in obj) return [i, obj[target - value]];
+
+    obj[value] = i;
+  }
+};

From d99ad18d7ea150932459f3c24fa85fc9f406aae0 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Wed, 16 Oct 2024 09:07:07 +0900
Subject: [PATCH 17/45] 104 / Maximum Depth of Binary Tree / Easy

---
 alexgoni/104_Maximum_Depth_of_Binary_Tree.js | 22 ++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 alexgoni/104_Maximum_Depth_of_Binary_Tree.js

diff --git a/alexgoni/104_Maximum_Depth_of_Binary_Tree.js b/alexgoni/104_Maximum_Depth_of_Binary_Tree.js
new file mode 100644
index 0000000..832b19c
--- /dev/null
+++ b/alexgoni/104_Maximum_Depth_of_Binary_Tree.js
@@ -0,0 +1,22 @@
+// 😢
+
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {number}
+ */
+var maxDepth = function (root) {
+  if (!root) return 0;
+
+  const leftDepth = maxDepth(root.left);
+  const rightDepth = maxDepth(root.right);
+
+  return Math.max(leftDepth, rightDepth) + 1;
+};

From 672e4d03fcbb001e48d21d26fe253a1774f8bc75 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Wed, 16 Oct 2024 09:08:09 +0900
Subject: [PATCH 18/45] 141 / Linked List Cycle / Easy / 15m

---
 alexgoni/141_Linked_List_Cycle.js | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 alexgoni/141_Linked_List_Cycle.js

diff --git a/alexgoni/141_Linked_List_Cycle.js b/alexgoni/141_Linked_List_Cycle.js
new file mode 100644
index 0000000..12475a8
--- /dev/null
+++ b/alexgoni/141_Linked_List_Cycle.js
@@ -0,0 +1,25 @@
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val) {
+ *     this.val = val;
+ *     this.next = null;
+ * }
+ */
+
+/**
+ * @param {ListNode} head
+ * @return {boolean}
+ */
+var hasCycle = function (head) {
+  const visited = new Map();
+  let current = head;
+
+  while (current) {
+    if (visited.has(current)) return true;
+
+    visited.set(current, true);
+    current = current.next;
+  }
+
+  return false;
+};

From 2c26983382fadcc9ee13f86346fbc00be7e75cc1 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Wed, 16 Oct 2024 09:10:00 +0900
Subject: [PATCH 19/45] 20 / Valid Parentheses / Easy / 12m

---
 alexgoni/20_Valid_Parentheses.js | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 alexgoni/20_Valid_Parentheses.js

diff --git a/alexgoni/20_Valid_Parentheses.js b/alexgoni/20_Valid_Parentheses.js
new file mode 100644
index 0000000..d77d2fc
--- /dev/null
+++ b/alexgoni/20_Valid_Parentheses.js
@@ -0,0 +1,28 @@
+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+var isValid = function (s) {
+  const stack = [];
+
+  for (let i = 0; i < s.length; i++) {
+    if (stack.length === 0) {
+      stack.push(s[i]);
+      continue;
+    }
+
+    if (s[i] === "(" || s[i] === "{" || s[i] === "[") stack.push(s[i]);
+    else if (s[i] === ")") {
+      if (stack[stack.length - 1] === "(") stack.pop();
+      else stack.push(s[i]);
+    } else if (s[i] === "}") {
+      if (stack[stack.length - 1] === "{") stack.pop();
+      else stack.push(s[i]);
+    } else if (s[i] === "]") {
+      if (stack[stack.length - 1] === "[") stack.pop();
+      else stack.push(s[i]);
+    }
+  }
+
+  return stack.length === 0;
+};

From 8ff63f8bafd579fae123fc93d44b76c87922d470 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Wed, 16 Oct 2024 09:19:47 +0900
Subject: [PATCH 20/45] 202 / Happy Number / Easy / 20m

---
 alexgoni/202_Happy_Number.js | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 alexgoni/202_Happy_Number.js

diff --git a/alexgoni/202_Happy_Number.js b/alexgoni/202_Happy_Number.js
new file mode 100644
index 0000000..87d8b84
--- /dev/null
+++ b/alexgoni/202_Happy_Number.js
@@ -0,0 +1,20 @@
+/**
+ * @param {number} n
+ * @return {boolean}
+ */
+var isHappy = function (n) {
+  const visited = {};
+
+  while (true) {
+    let sum = 0;
+    [...String(n)].forEach((str) => {
+      sum += Number(str) ** 2;
+    });
+
+    if (sum === 0) return true;
+    if (visited[sum]) return false;
+
+    visited[sum] = true;
+    n = sum;
+  }
+};

From 33b6af70e76eb2831baa99f6014fb34494fb4da6 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Mon, 4 Nov 2024 09:51:22 +0900
Subject: [PATCH 21/45] 136 / Single Number / Easy / 3m

---
 alexgoni/136_Single_Number.js | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
 create mode 100644 alexgoni/136_Single_Number.js

diff --git a/alexgoni/136_Single_Number.js b/alexgoni/136_Single_Number.js
new file mode 100644
index 0000000..954952b
--- /dev/null
+++ b/alexgoni/136_Single_Number.js
@@ -0,0 +1,15 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var singleNumber = function (nums) {
+  const obj = {};
+
+  for (const num of nums) {
+    obj[num] = (obj[num] || 0) + 1;
+  }
+
+  for (const key in obj) {
+    if (obj[key] === 1) return Number(key);
+  }
+};

From cf7a089b5466975914d5f5c2f27ceb1ac1323111 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Mon, 4 Nov 2024 10:27:01 +0900
Subject: [PATCH 22/45] 110 / Balanced Binary Tree / Easy

---
 alexgoni/110_Balanced_Binary_Tree.js | 31 ++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 alexgoni/110_Balanced_Binary_Tree.js

diff --git a/alexgoni/110_Balanced_Binary_Tree.js b/alexgoni/110_Balanced_Binary_Tree.js
new file mode 100644
index 0000000..b9f20ff
--- /dev/null
+++ b/alexgoni/110_Balanced_Binary_Tree.js
@@ -0,0 +1,31 @@
+// 😢
+
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {boolean}
+ */
+var isBalanced = function (root) {
+  let result = true;
+
+  const maxDepth = (root) => {
+    if (!root) return 0;
+
+    const leftDepth = maxDepth(root.left);
+    const rightDepth = maxDepth(root.right);
+
+    if (Math.abs(leftDepth - rightDepth) > 1) result = false;
+
+    return Math.max(leftDepth, rightDepth) + 1;
+  };
+
+  maxDepth(root);
+  return result;
+};

From f480da2d81cf79e8453a0916da8691d94863e6bb Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Mon, 4 Nov 2024 11:00:27 +0900
Subject: [PATCH 23/45] 973 / K Closest Points to Origin / Medium / 5m

---
 alexgoni/973_K_Closest_Points_to_Origin.js | 9 +++++++++
 1 file changed, 9 insertions(+)
 create mode 100644 alexgoni/973_K_Closest_Points_to_Origin.js

diff --git a/alexgoni/973_K_Closest_Points_to_Origin.js b/alexgoni/973_K_Closest_Points_to_Origin.js
new file mode 100644
index 0000000..b8065b0
--- /dev/null
+++ b/alexgoni/973_K_Closest_Points_to_Origin.js
@@ -0,0 +1,9 @@
+/**
+ * @param {number[][]} points
+ * @param {number} k
+ * @return {number[][]}
+ */
+var kClosest = function (points, k) {
+  points.sort((a, b) => a[0] ** 2 + a[1] ** 2 - (b[0] ** 2 + b[1] ** 2));
+  return points.slice(0, k);
+};

From d321a7b4bb62ee3f4dc04e0be242ba814869ab1f Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 5 Nov 2024 09:51:17 +0900
Subject: [PATCH 24/45] 155 / Min Stack / Medium / 11m

---
 alexgoni/155_Min_Stack.js | 44 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 alexgoni/155_Min_Stack.js

diff --git a/alexgoni/155_Min_Stack.js b/alexgoni/155_Min_Stack.js
new file mode 100644
index 0000000..8d88fed
--- /dev/null
+++ b/alexgoni/155_Min_Stack.js
@@ -0,0 +1,44 @@
+var MinStack = function () {
+  this.min = Number.POSITIVE_INFINITY;
+  this.stack = [];
+};
+
+/**
+ * @param {number} val
+ * @return {void}
+ */
+MinStack.prototype.push = function (val) {
+  this.stack.push(val);
+  if (this.min > val) this.min = val;
+};
+
+/**
+ * @return {void}
+ */
+MinStack.prototype.pop = function () {
+  this.stack.pop();
+  this.min = Math.min(...this.stack);
+};
+
+/**
+ * @return {number}
+ */
+MinStack.prototype.top = function () {
+  return this.stack[this.stack.length - 1];
+};
+
+/**
+ * @return {number}
+ */
+MinStack.prototype.getMin = function () {
+  return this.min;
+};
+
+/**
+ * Your MinStack object will be instantiated and called as such:
+ * var obj = new MinStack()
+ * obj.push(val)
+ * obj.pop()
+ * var param_3 = obj.top()
+ * var param_4 = obj.getMin()
+ */

From 9b96eb4bf61b22d51de3f131970bb6536b047fbb Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 5 Nov 2024 10:39:19 +0900
Subject: [PATCH 25/45] 54 / Spiral Matrix / Medium / 60m

---
 alexgoni/54_Spiral_Matrix.js | 46 ++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 alexgoni/54_Spiral_Matrix.js

diff --git a/alexgoni/54_Spiral_Matrix.js b/alexgoni/54_Spiral_Matrix.js
new file mode 100644
index 0000000..66fd542
--- /dev/null
+++ b/alexgoni/54_Spiral_Matrix.js
@@ -0,0 +1,46 @@
+var spiralOrder = function (matrix) {
+  const result = [];
+  let m = matrix[0].length;
+  let n = matrix.length;
+  let direction = 0;
+  let spiralCount = 0;
+  let i = 0,
+    j = 0;
+
+  for (let count = 0; count < m * n; count++) {
+    result.push(matrix[i][j]);
+
+    if (direction === 0) {
+      if (j < m - 1 - spiralCount) {
+        j++;
+      } else {
+        direction = 1;
+        i++;
+      }
+    } else if (direction === 1) {
+      if (i < n - 1 - spiralCount) {
+        i++;
+      } else {
+        direction = 2;
+        j--;
+      }
+    } else if (direction === 2) {
+      if (j > spiralCount) {
+        j--;
+      } else {
+        direction = 3;
+        i--;
+      }
+    } else if (direction === 3) {
+      if (i > spiralCount + 1) {
+        i--;
+      } else {
+        direction = 0;
+        spiralCount++;
+        j++;
+      }
+    }
+  }
+
+  return result;
+};

From 856d432b7e2b5b1aba795c0dd2f9b19700ed0f63 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 5 Nov 2024 20:17:47 +0900
Subject: [PATCH 26/45] 338 / Counting Bits / Easy / 23m

---
 alexgoni/338_Counting_Bits.js | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 alexgoni/338_Counting_Bits.js

diff --git a/alexgoni/338_Counting_Bits.js b/alexgoni/338_Counting_Bits.js
new file mode 100644
index 0000000..3d46cc5
--- /dev/null
+++ b/alexgoni/338_Counting_Bits.js
@@ -0,0 +1,19 @@
+/**
+ * @param {number} n
+ * @return {number[]}
+ */
+var countBits = function (n) {
+  const result = [];
+
+  for (let i = 0; i <= n; i++) {
+    const str = i.toString(2);
+    let count = 0;
+    [...str].forEach((char) => {
+      if (char === "1") count++;
+    });
+
+    result.push(count);
+  }
+
+  return result;
+};

From 50cc2e8aae483e8920c7cc94bf6b7306e68c8c59 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 5 Nov 2024 20:19:55 +0900
Subject: [PATCH 27/45] 70 / Climbing Stairs / Easy / 25m

---
 alexgoni/70_Climbing_Stairs.js | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 alexgoni/70_Climbing_Stairs.js

diff --git a/alexgoni/70_Climbing_Stairs.js b/alexgoni/70_Climbing_Stairs.js
new file mode 100644
index 0000000..606676b
--- /dev/null
+++ b/alexgoni/70_Climbing_Stairs.js
@@ -0,0 +1,25 @@
+/**
+ * @param {number} n
+ * @return {number}
+ */
+var climbStairs = function (n) {
+  let result = 0;
+
+  for (let i = 0; i <= n / 2; i++) {
+    const count2 = i;
+    const count1 = n - 2 * count2;
+
+    result += combination(count1 + count2, count2);
+  }
+
+  return result;
+};
+
+function combination(n, r) {
+  let result = 1;
+
+  for (let i = 0; i < r; i++) result *= n - i;
+  for (let i = 1; i <= r; i++) result /= i;
+
+  return result;
+}

From 5a2e1090a9a1ca903df5fc6cfbb14c3a62c09c68 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 5 Nov 2024 20:21:40 +0900
Subject: [PATCH 28/45] 21 / Merge Two Sorted Lists / Easy

---
 alexgoni/21_Merge_Two_Sorted_Lists.js | 54 +++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 alexgoni/21_Merge_Two_Sorted_Lists.js

diff --git a/alexgoni/21_Merge_Two_Sorted_Lists.js b/alexgoni/21_Merge_Two_Sorted_Lists.js
new file mode 100644
index 0000000..312ca9d
--- /dev/null
+++ b/alexgoni/21_Merge_Two_Sorted_Lists.js
@@ -0,0 +1,54 @@
+// 😢
+
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val, next) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.next = (next===undefined ? null : next)
+ * }
+ */
+/**
+ * @param {ListNode} list1
+ * @param {ListNode} list2
+ * @return {ListNode}
+ */
+var mergeTwoLists = function (list1, list2) {
+  if (!list1 && !list2) return null;
+  else if (!list1) return list2;
+  else if (!list2) return list1;
+
+  let head;
+  let current1 = list1;
+  let current2 = list2;
+  if (current1.val >= current2.val) {
+    head = current2;
+    current2 = current2.next;
+  } else {
+    head = current1;
+    current1 = current1.next;
+  }
+
+  let current = head;
+  while (current1 || current2) {
+    if (current1 === null) {
+      current.next = current2;
+      break;
+    }
+    if (current2 === null) {
+      current.next = current1;
+      break;
+    }
+
+    if (current1.val >= current2.val) {
+      current.next = current2;
+      current2 = current2.next;
+    } else {
+      current.next = current1;
+      current1 = current1.next;
+    }
+
+    current = current.next;
+  }
+
+  return head;
+};

From 51c2532adc6b3e340da6c8f792b5f0eae53b2276 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 5 Nov 2024 20:23:42 +0900
Subject: [PATCH 29/45] 1046 / Last Stone Weight / Easy / 55m

---
 alexgoni/1046_Last_Stone_Weight.js | 36 ++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)
 create mode 100644 alexgoni/1046_Last_Stone_Weight.js

diff --git a/alexgoni/1046_Last_Stone_Weight.js b/alexgoni/1046_Last_Stone_Weight.js
new file mode 100644
index 0000000..cc3475a
--- /dev/null
+++ b/alexgoni/1046_Last_Stone_Weight.js
@@ -0,0 +1,36 @@
+/**
+ * @param {number[]} stones
+ * @return {number}
+ */
+var lastStoneWeight = function (stones) {
+  while (stones.length > 1) {
+    let maxIdx, secondMaxIdx;
+    if (stones[0] >= stones[1]) {
+      maxIdx = 0;
+      secondMaxIdx = 1;
+    } else {
+      maxIdx = 1;
+      secondMaxIdx = 0;
+    }
+
+    for (let i = 2; i < stones.length; i++) {
+      if (stones[maxIdx] <= stones[i]) {
+        secondMaxIdx = maxIdx;
+        maxIdx = i;
+      } else if (stones[secondMaxIdx] < stones[i]) {
+        secondMaxIdx = i;
+      }
+    }
+
+    if (stones[maxIdx] === stones[secondMaxIdx]) {
+      stones = stones.filter(
+        (_, idx) => idx !== maxIdx && idx !== secondMaxIdx
+      );
+    } else {
+      stones[maxIdx] = stones[maxIdx] - stones[secondMaxIdx];
+      stones.splice(secondMaxIdx, 1);
+    }
+  }
+
+  return stones.length > 0 ? stones[0] : 0;
+};

From 086da91258e7b9f1cef143b00bd49093a6f15095 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 5 Nov 2024 20:53:18 +0900
Subject: [PATCH 30/45] 48 / Rotate Image / Medium / 20m

---
 alexgoni/48_Rotate_Image.js | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 alexgoni/48_Rotate_Image.js

diff --git a/alexgoni/48_Rotate_Image.js b/alexgoni/48_Rotate_Image.js
new file mode 100644
index 0000000..e7bc42e
--- /dev/null
+++ b/alexgoni/48_Rotate_Image.js
@@ -0,0 +1,22 @@
+/**
+ * @param {number[][]} matrix
+ * @return {void} Do not return anything, modify matrix in-place instead.
+ */
+var rotate = function (matrix) {
+  const copy = [];
+  const n = matrix.length;
+
+  for (let i = 0; i < n; i++) {
+    const row = [];
+    for (let j = 0; j < n; j++) {
+      row.push(matrix[i][j]);
+    }
+    copy.push(row);
+  }
+
+  for (let i = 0; i < n; i++) {
+    for (let j = 0; j < n; j++) {
+      matrix[i][j] = copy[n - 1 - j][i];
+    }
+  }
+};

From 0b15f28e265cccfbd3e145a235c5746b5f6d186c Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Wed, 13 Nov 2024 11:15:12 +0900
Subject: [PATCH 31/45] 543 / Diameter of Binary Tree / Easy / 15m

---
 alexgoni/543_Diameter_of_Binary_Tree.js | 28 +++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 alexgoni/543_Diameter_of_Binary_Tree.js

diff --git a/alexgoni/543_Diameter_of_Binary_Tree.js b/alexgoni/543_Diameter_of_Binary_Tree.js
new file mode 100644
index 0000000..09b443d
--- /dev/null
+++ b/alexgoni/543_Diameter_of_Binary_Tree.js
@@ -0,0 +1,28 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {number}
+ */
+var diameterOfBinaryTree = function (root) {
+  let result = 0;
+
+  const maxDepth = (node) => {
+    if (node === null) return 0;
+
+    const leftDepth = maxDepth(node.left);
+    const rightDepth = maxDepth(node.right);
+
+    result = Math.max(result, leftDepth + rightDepth);
+    return Math.max(leftDepth, rightDepth) + 1;
+  };
+
+  maxDepth(root);
+  return result;
+};

From 6a6bf322aa3c8b6c65086cafd40033f09a438587 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Wed, 13 Nov 2024 11:16:57 +0900
Subject: [PATCH 32/45] 128 / Longest Consecutive Sequence / Medium / 23m

---
 alexgoni/128_Longest_Consecutive_Sequence.js | 23 ++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 alexgoni/128_Longest_Consecutive_Sequence.js

diff --git a/alexgoni/128_Longest_Consecutive_Sequence.js b/alexgoni/128_Longest_Consecutive_Sequence.js
new file mode 100644
index 0000000..c980776
--- /dev/null
+++ b/alexgoni/128_Longest_Consecutive_Sequence.js
@@ -0,0 +1,23 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var longestConsecutive = function (nums) {
+  if (nums.length === 0) return 0;
+
+  let result = 1;
+  let temp = 1;
+  nums = [...new Set(nums)];
+  nums.sort((a, b) => a - b);
+
+  for (let i = 0; i < nums.length - 1; i++) {
+    if (nums[i + 1] === nums[i] + 1) temp++;
+    else {
+      result = Math.max(result, temp);
+      temp = 1;
+    }
+  }
+
+  result = Math.max(result, temp);
+  return result;
+};

From 4c9c8a021bb77ed88089995d73ed1bd9e416dbae Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Wed, 13 Nov 2024 11:19:01 +0900
Subject: [PATCH 33/45] 371 / Sum of Two Integers / Medium

---
 alexgoni/371_Sum_of_Two_Integers.js | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 alexgoni/371_Sum_of_Two_Integers.js

diff --git a/alexgoni/371_Sum_of_Two_Integers.js b/alexgoni/371_Sum_of_Two_Integers.js
new file mode 100644
index 0000000..18e324e
--- /dev/null
+++ b/alexgoni/371_Sum_of_Two_Integers.js
@@ -0,0 +1,20 @@
+// 😢
+
+/**
+ * @param {number} a
+ * @param {number} b
+ * @return {number}
+ */
+var getSum = function (a, b) {
+  let x = a;
+  let y = b;
+
+  while (y !== 0) {
+    const sumWithoutCarry = x ^ y;
+    const carry = (x & y) << 1;
+
+    x = sumWithoutCarry;
+    y = carry;
+  }
+  return x;
+};

From 8146bd27ab2e888858b6ff99f14046d7cae44be7 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Wed, 13 Nov 2024 11:20:09 +0900
Subject: [PATCH 34/45] 208 / Implement Trie / Medium / 30m

---
 alexgoni/208_Implement_Trie.js | 51 ++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)
 create mode 100644 alexgoni/208_Implement_Trie.js

diff --git a/alexgoni/208_Implement_Trie.js b/alexgoni/208_Implement_Trie.js
new file mode 100644
index 0000000..a7e2abb
--- /dev/null
+++ b/alexgoni/208_Implement_Trie.js
@@ -0,0 +1,51 @@
+class Node {
+  constructor({ key, data = null }) {
+    this.key = key;
+    this.data = data;
+    this.children = {};
+  }
+}
+
+class Trie {
+  constructor() {
+    this.head = new Node({ key: null });
+  }
+
+  insert(word) {
+    let currentNode = this.head;
+
+    for (let i = 0; i < word.length; i++) {
+      const str = word[i];
+      const newNode = currentNode.children?.[str]
+        ? currentNode.children[str]
+        : new Node({ key: str });
+
+      if (i === word.length - 1) newNode.data = word;
+      currentNode.children[str] = newNode;
+      currentNode = newNode;
+    }
+  }
+
+  search(word) {
+    let currentNode = this.head;
+
+    for (const str of word) {
+      if (currentNode.children[str]) currentNode = currentNode.children[str];
+      else return false;
+    }
+
+    if (currentNode.data) return true;
+    else return false;
+  }
+
+  startsWith(prefix) {
+    let currentNode = this.head;
+
+    for (const str of prefix) {
+      if (currentNode.children[str]) currentNode = currentNode.children[str];
+      else return false;
+    }
+
+    return true;
+  }
+}

From 790d80a00e16438e6ac17e6281b6a2738c204e83 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Wed, 13 Nov 2024 11:21:03 +0900
Subject: [PATCH 35/45] 226 / Invert Binary Tree / Easy / 13m

---
 alexgoni/226_Invert_Binary_Tree.js | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 alexgoni/226_Invert_Binary_Tree.js

diff --git a/alexgoni/226_Invert_Binary_Tree.js b/alexgoni/226_Invert_Binary_Tree.js
new file mode 100644
index 0000000..d19d098
--- /dev/null
+++ b/alexgoni/226_Invert_Binary_Tree.js
@@ -0,0 +1,22 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {TreeNode}
+ */
+var invertTree = function (root) {
+  if (!root) return root;
+
+  invertTree(root.left);
+  invertTree(root.right);
+
+  [root.left, root.right] = [root.right, root.left];
+
+  return root;
+};

From b23d72e0b634c1d69682e3c1406a75cd72e27593 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 26 Nov 2024 21:54:14 +0900
Subject: [PATCH 36/45] 102 / Binary Tree Level Order Traversal / Medium

---
 .../102_Binary_Tree_Level_Order_Traversal.js  | 37 +++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 alexgoni/102_Binary_Tree_Level_Order_Traversal.js

diff --git a/alexgoni/102_Binary_Tree_Level_Order_Traversal.js b/alexgoni/102_Binary_Tree_Level_Order_Traversal.js
new file mode 100644
index 0000000..893aefd
--- /dev/null
+++ b/alexgoni/102_Binary_Tree_Level_Order_Traversal.js
@@ -0,0 +1,37 @@
+// 😢
+
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {number[][]}
+ */
+var levelOrder = function (root) {
+  if (!root) return [];
+
+  const result = [];
+  const q = [root];
+
+  while (q.length > 0) {
+    const level = [];
+    const size = q.length;
+
+    for (let i = 0; i < size; i++) {
+      const node = q.shift();
+      level.push(node.val);
+
+      if (node.left) q.push(node.left);
+      if (node.right) q.push(node.right);
+    }
+
+    result.push(level);
+  }
+
+  return result;
+};

From ab11a2f4b412827e186f96ce5dbea4121409b22c Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 26 Nov 2024 21:58:06 +0900
Subject: [PATCH 37/45] 213 / House Rober ll / Medium / 25m

---
 alexgoni/213_House_Robber_ll.js | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 alexgoni/213_House_Robber_ll.js

diff --git a/alexgoni/213_House_Robber_ll.js b/alexgoni/213_House_Robber_ll.js
new file mode 100644
index 0000000..f348bb7
--- /dev/null
+++ b/alexgoni/213_House_Robber_ll.js
@@ -0,0 +1,30 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var rob = function (nums) {
+  if (nums.length <= 3) return Math.max(...nums);
+
+  const firstNums = nums.slice(0, nums.length - 1);
+  const secondNums = nums.slice(1);
+  const firstDp = [firstNums[0], firstNums[1]];
+  const secondDp = [secondNums[0], secondNums[1]];
+
+  for (let i = 2; i < firstNums.length; i++) {
+    if (i === 2) firstDp[i] = firstDp[0] + firstNums[i];
+    else firstDp[i] = Math.max(firstDp[i - 2], firstDp[i - 3]) + firstNums[i];
+  }
+
+  for (let i = 2; i < secondNums.length; i++) {
+    if (i === 2) secondDp[i] = secondDp[0] + secondNums[i];
+    else
+      secondDp[i] = Math.max(secondDp[i - 2], secondDp[i - 3]) + secondNums[i];
+  }
+
+  return Math.max(
+    firstDp[firstNums.length - 1],
+    firstDp[firstNums.length - 2],
+    secondDp[secondNums.length - 1],
+    secondDp[secondNums.length - 2]
+  );
+};

From c93b49c72498721219f3c1aba8a9806b656ded0f Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 26 Nov 2024 21:59:32 +0900
Subject: [PATCH 38/45] 207 / Course Schedule / Medium

---
 alexgoni/207_Course_Schedule.js | 34 +++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 alexgoni/207_Course_Schedule.js

diff --git a/alexgoni/207_Course_Schedule.js b/alexgoni/207_Course_Schedule.js
new file mode 100644
index 0000000..2423e36
--- /dev/null
+++ b/alexgoni/207_Course_Schedule.js
@@ -0,0 +1,34 @@
+// 😢
+
+/**
+ * @param {number} numCourses
+ * @param {number[][]} prerequisites
+ * @return {boolean}
+ */
+var canFinish = function (numCourses, prerequisites) {
+  const graph = Array.from({ length: numCourses }, () => []);
+  for (const [a, b] of prerequisites) {
+    graph[b].push(a);
+  }
+
+  const visited = Array(numCourses).fill(0);
+
+  const hasCycle = (cource) => {
+    if (visited[cource] === 1) return true;
+    if (visited[cource] === 2) return false;
+
+    visited[cource] = 1;
+    for (const neighbor of graph[cource]) {
+      if (hasCycle(neighbor)) return true;
+    }
+    visited[cource] = 2;
+
+    return false;
+  };
+
+  for (let i = 0; i < numCourses; i++) {
+    if (hasCycle(i)) return false;
+  }
+
+  return true;
+};

From 6e01ac4caeb42f2fc00863dafdeac2f7302b9937 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 26 Nov 2024 22:01:23 +0900
Subject: [PATCH 39/45] 150 / Evaluate Reverse Polish Notation / Medium / 36m

---
 .../150_Evaluate_Reverse_Polish_Notation.js   | 48 +++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 alexgoni/150_Evaluate_Reverse_Polish_Notation.js

diff --git a/alexgoni/150_Evaluate_Reverse_Polish_Notation.js b/alexgoni/150_Evaluate_Reverse_Polish_Notation.js
new file mode 100644
index 0000000..454d27d
--- /dev/null
+++ b/alexgoni/150_Evaluate_Reverse_Polish_Notation.js
@@ -0,0 +1,48 @@
+// /**
+//  * @param {string[]} tokens
+//  * @return {number}
+//  */
+// var evalRPN = function(tokens) {
+//     let i = 0;
+
+//     while(tokens.length > 1) {
+//         if(isNaN(tokens[i])) {
+//             let temp;
+
+//             if(tokens[i] === "+") temp = Number(tokens[i-2]) + Number(tokens[i-1]);
+//             if(tokens[i] === "-") temp = Number(tokens[i-2]) - Number(tokens[i-1]);
+//             if(tokens[i] === "*") temp = Number(tokens[i-2]) * Number(tokens[i-1]);
+//             if(tokens[i] === "/") temp = Math.trunc(Number(tokens[i-2]) / Number(tokens[i-1]));
+
+//             tokens.splice(i-2, 3, temp);
+//             i = 0;
+//         }
+
+//         i++;
+//     }
+
+//     return +tokens[0];
+// };
+
+/**
+ * @param {string[]} tokens
+ * @return {number}
+ */
+var evalRPN = function (tokens) {
+  const stack = [];
+
+  for (let token of tokens) {
+    if (!isNaN(token)) stack.push(Number(token));
+    else {
+      const b = stack.pop();
+      const a = stack.pop();
+
+      if (token === "+") stack.push(a + b);
+      if (token === "-") stack.push(a - b);
+      if (token === "*") stack.push(a * b);
+      if (token === "/") stack.push(Math.trunc(a / b));
+    }
+  }
+
+  return stack.pop();
+};

From df0dc158b9e4b449706d439a6351e620dcb383fb Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 26 Nov 2024 22:47:32 +0900
Subject: [PATCH 40/45] 572 / Subtree of Another Tree / Easy

---
 alexgoni/572_Subtree_of_Another_Tree.js | 30 +++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 alexgoni/572_Subtree_of_Another_Tree.js

diff --git a/alexgoni/572_Subtree_of_Another_Tree.js b/alexgoni/572_Subtree_of_Another_Tree.js
new file mode 100644
index 0000000..893eaf4
--- /dev/null
+++ b/alexgoni/572_Subtree_of_Another_Tree.js
@@ -0,0 +1,30 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @param {TreeNode} subRoot
+ * @return {boolean}
+ */
+var isSubtree = function (root, subRoot) {
+  if (!root) return false;
+
+  if (isSameTree(root, subRoot)) return true;
+
+  return isSubtree(root.left, subRoot) || isSubtree(root.right, subRoot);
+};
+
+function isSameTree(root1, root2) {
+  if (!root1 && !root2) return true;
+  if (!root1 || !root2) return false;
+  if (root1.val !== root2.val) return false;
+
+  return (
+    isSameTree(root1.left, root2.left) && isSameTree(root1.right, root2.right)
+  );
+}

From 5473baabe01d21d2d2729e9de57ba0c4e07c4615 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 26 Nov 2024 22:49:07 +0900
Subject: [PATCH 41/45] 56 / Merge Intervals / Medium / 30m

---
 alexgoni/56_Merge_Intervals.js | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 alexgoni/56_Merge_Intervals.js

diff --git a/alexgoni/56_Merge_Intervals.js b/alexgoni/56_Merge_Intervals.js
new file mode 100644
index 0000000..9b74555
--- /dev/null
+++ b/alexgoni/56_Merge_Intervals.js
@@ -0,0 +1,22 @@
+/**
+ * @param {number[][]} intervals
+ * @return {number[][]}
+ */
+var merge = function (intervals) {
+  const result = [];
+  intervals.sort((a, b) => a[0] - b[0]);
+
+  let i = 0;
+  while (i < intervals.length - 1) {
+    if (intervals[i][1] >= intervals[i + 1][0]) {
+      intervals.splice(i, 2, [
+        intervals[i][0],
+        Math.max(intervals[i][1], intervals[i + 1][1]),
+      ]);
+    } else {
+      i++;
+    }
+  }
+
+  return intervals;
+};

From 3ba5e6cf3818dd79eed477d32f5f500277830190 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 26 Nov 2024 22:50:52 +0900
Subject: [PATCH 42/45] 1584 / Min Cost to Connect All Points / Medium

---
 .../1584_Min_Cost_to_Connect_All_Points.js    | 37 +++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 alexgoni/1584_Min_Cost_to_Connect_All_Points.js

diff --git a/alexgoni/1584_Min_Cost_to_Connect_All_Points.js b/alexgoni/1584_Min_Cost_to_Connect_All_Points.js
new file mode 100644
index 0000000..16419c7
--- /dev/null
+++ b/alexgoni/1584_Min_Cost_to_Connect_All_Points.js
@@ -0,0 +1,37 @@
+/**
+ * @param {number[][]} points
+ * @return {number}
+ */
+var minCostConnectPoints = function (points) {
+  const n = points.length;
+  const visited = Array(n).fill(false);
+  const minDist = Array(n).fill(Infinity);
+  minDist[0] = 0;
+  let result = 0;
+
+  for (let i = 0; i < n; i++) {
+    let currMin = Infinity;
+    let currNode = -1;
+
+    for (let j = 0; j < n; j++) {
+      if (!visited[j] && minDist[j] < currMin) {
+        currMin = minDist[j];
+        currNode = j;
+      }
+    }
+
+    visited[currNode] = true;
+    result += currMin;
+
+    for (let j = 0; j < n; j++) {
+      if (!visited[j]) {
+        const cost =
+          Math.abs(points[currNode][0] - points[j][0]) +
+          Math.abs(points[currNode][1] - points[j][1]);
+        minDist[j] = Math.min(minDist[j], cost);
+      }
+    }
+  }
+
+  return result;
+};

From fcd3812d4aa4846d8a83ccbe69099d3487659b05 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 26 Nov 2024 22:52:45 +0900
Subject: [PATCH 43/45] 235 / Lowest Common Ancestor of a Binary Search Tree /
 Medium

---
 .../1584_Min_Cost_to_Connect_All_Points.js    |  2 ++
 ...Common_Ancestor_of_a_Binary_Search_Tree.js | 27 +++++++++++++++++++
 2 files changed, 29 insertions(+)
 create mode 100644 alexgoni/235_Lowest_Common_Ancestor_of_a_Binary_Search_Tree.js

diff --git a/alexgoni/1584_Min_Cost_to_Connect_All_Points.js b/alexgoni/1584_Min_Cost_to_Connect_All_Points.js
index 16419c7..9882b6d 100644
--- a/alexgoni/1584_Min_Cost_to_Connect_All_Points.js
+++ b/alexgoni/1584_Min_Cost_to_Connect_All_Points.js
@@ -1,3 +1,5 @@
+// 😢
+
 /**
  * @param {number[][]} points
  * @return {number}
diff --git a/alexgoni/235_Lowest_Common_Ancestor_of_a_Binary_Search_Tree.js b/alexgoni/235_Lowest_Common_Ancestor_of_a_Binary_Search_Tree.js
new file mode 100644
index 0000000..d2c48bc
--- /dev/null
+++ b/alexgoni/235_Lowest_Common_Ancestor_of_a_Binary_Search_Tree.js
@@ -0,0 +1,27 @@
+// 😢
+
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+
+/**
+ * @param {TreeNode} root
+ * @param {TreeNode} p
+ * @param {TreeNode} q
+ * @return {TreeNode}
+ */
+var lowestCommonAncestor = function (root, p, q) {
+  if (p.val < root.val && q.val < root.val) {
+    return lowestCommonAncestor(root.left, p, q);
+  }
+
+  if (p.val > root.val && q.val > root.val) {
+    return lowestCommonAncestor(root.right, p, q);
+  }
+
+  return root;
+};

From 09a485fb63d8f6a4eb0a6f50903974c2835b9e35 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 26 Nov 2024 22:53:34 +0900
Subject: [PATCH 44/45] 139 / Word Break / Medium

---
 alexgoni/139_Word_Break.js | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 alexgoni/139_Word_Break.js

diff --git a/alexgoni/139_Word_Break.js b/alexgoni/139_Word_Break.js
new file mode 100644
index 0000000..601f052
--- /dev/null
+++ b/alexgoni/139_Word_Break.js
@@ -0,0 +1,23 @@
+// 😢
+
+/**
+ * @param {string} s
+ * @param {string[]} wordDict
+ * @return {boolean}
+ */
+var wordBreak = function (s, wordDict) {
+  const wordSet = new Set(wordDict);
+  const dp = Array.from({ length: s.length + 1 }).fill(false);
+  dp[0] = true;
+
+  for (let i = 1; i <= s.length; i++) {
+    for (let j = 0; j < i; j++) {
+      if (dp[j] && wordSet.has(s.slice(j, i))) {
+        dp[i] = true;
+        break;
+      }
+    }
+  }
+
+  return dp[s.length];
+};

From bdcf97708b4fc554e0055e281451a4728861f0c0 Mon Sep 17 00:00:00 2001
From: alexgoni <goni000211@gmail.com>
Date: Tue, 26 Nov 2024 22:55:17 +0900
Subject: [PATCH 45/45] 215 / Kth Largest Element in an Array / Medium

---
 .../215_Kth_Largest_Element_in_an_Array.js    | 96 +++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 alexgoni/215_Kth_Largest_Element_in_an_Array.js

diff --git a/alexgoni/215_Kth_Largest_Element_in_an_Array.js b/alexgoni/215_Kth_Largest_Element_in_an_Array.js
new file mode 100644
index 0000000..e82715b
--- /dev/null
+++ b/alexgoni/215_Kth_Largest_Element_in_an_Array.js
@@ -0,0 +1,96 @@
+// 😢
+
+/**
+ * @param {number[]} nums
+ * @param {number} k
+ * @return {number}
+ */
+var findKthLargest = function (nums, k) {
+  const heap = new MaxBinaryHeap();
+
+  for (const num of nums) {
+    heap.insert(num);
+  }
+
+  for (let i = 0; i < k; i++) {
+    const extractedValue = heap.extractMax();
+    if (i === k - 1) return extractedValue;
+  }
+};
+
+class MaxBinaryHeap {
+  constructor() {
+    this.values = [];
+  }
+
+  insert(value) {
+    this.values.push(value);
+    this.#bubbleUp();
+
+    return this.values;
+  }
+
+  extractMax() {
+    const extractedValue = this.values[0];
+    const poppedValue = this.values.pop();
+
+    if (this.values.length === 0) return extractedValue;
+
+    this.values[0] = poppedValue;
+    this.#sinkDown();
+
+    return extractedValue;
+  }
+
+  #bubbleUp() {
+    let currentIndex = this.values.length - 1;
+    const currentValue = this.values[currentIndex];
+
+    while (currentIndex > 0) {
+      const parentIndex = Math.floor((currentIndex - 1) / 2);
+      const parentValue = this.values[parentIndex];
+
+      if (parentValue >= currentValue) break;
+
+      this.values[parentIndex] = currentValue;
+      this.values[currentIndex] = parentValue;
+
+      currentIndex = parentIndex;
+    }
+  }
+
+  #sinkDown() {
+    let currentIndex = 0;
+    const currentValue = this.values[currentIndex];
+    const length = this.values.length;
+
+    while (true) {
+      let leftChildIndex = currentIndex * 2 + 1;
+      let rightChildIndex = currentIndex * 2 + 2;
+      let leftChildValue, rightChildValue;
+      let swapWith = null;
+
+      if (leftChildIndex < length) {
+        leftChildValue = this.values[leftChildIndex];
+        if (leftChildValue > currentValue) swapWith = leftChildIndex;
+      }
+
+      if (rightChildIndex < length) {
+        rightChildValue = this.values[rightChildIndex];
+        if (
+          (!swapWith && rightChildValue > currentValue) ||
+          (swapWith && rightChildValue > leftChildValue)
+        ) {
+          swapWith = rightChildIndex;
+        }
+      }
+
+      if (!swapWith) break;
+
+      this.values[currentIndex] = this.values[swapWith];
+      this.values[swapWith] = currentValue;
+
+      currentIndex = swapWith;
+    }
+  }
+}