diff --git "a/JooKangsan/10\354\243\274\354\260\250/139_Word_Break.js" "b/JooKangsan/10\354\243\274\354\260\250/139_Word_Break.js"
new file mode 100644
index 0000000..955cf04
--- /dev/null
+++ "b/JooKangsan/10\354\243\274\354\260\250/139_Word_Break.js"
@@ -0,0 +1,32 @@
+
+
+/**
+ * @param {string} s
+ * @param {string[]} wordDict
+ * @return {boolean}
+ */
+var wordBreak = function(s, wordDict) {
+    const memo = new Map();
+    
+    function dp(str, i = 0) {
+        if (str.length === 0) return true;
+        if (i >= wordDict.length) return false;
+ 
+        const key = str + ',' + i;
+        if (memo.has(key)) return memo.get(key);
+        
+        let word = wordDict[i];
+        if (str.slice(0, word.length) === word) {
+            if (dp(str.slice(word.length), 0)) {
+                memo.set(key, true);
+                return true;
+            }
+        }
+        
+        const result = dp(str, i + 1);
+        memo.set(key, result);
+        return result;
+    }
+    
+    return dp(s);
+};
\ No newline at end of file
diff --git "a/JooKangsan/10\354\243\274\354\260\250/1584_Min_Cost_to_Connect_All_Points.js" "b/JooKangsan/10\354\243\274\354\260\250/1584_Min_Cost_to_Connect_All_Points.js"
new file mode 100644
index 0000000..2ffa792
--- /dev/null
+++ "b/JooKangsan/10\354\243\274\354\260\250/1584_Min_Cost_to_Connect_All_Points.js"
@@ -0,0 +1,34 @@
+/**
+ * @param {number[][]} points
+ * @return {number}
+ */
+var minCostConnectPoints = function (points) {
+  const n = points.length;
+  const visited = new Array(n).fill(false);
+  const minDist = new Array(n).fill(Infinity);
+  minDist[0] = 0;
+  let result = 0;
+
+  for (let i = 0; i < n; i++) {
+    let x = -1;
+    for (let j = 0; j < n; j++) {
+      if (!visited[j] && (x === -1 || minDist[j] < minDist[x])) {
+        x = j;
+      }
+    }
+
+    visited[x] = true;
+    result += minDist[x];
+
+    for (let k = 0; k < n; k++) {
+      if (!visited[k]) {
+        const dist =
+          Math.abs(points[x][0] - points[k][0]) +
+          Math.abs(points[x][1] - points[k][1]);
+        minDist[k] = Math.min(minDist[k], dist);
+      }
+    }
+  }
+
+  return result;
+};
diff --git "a/JooKangsan/10\354\243\274\354\260\250/215_Kth_Largest_Element_in_an_Array.js" "b/JooKangsan/10\354\243\274\354\260\250/215_Kth_Largest_Element_in_an_Array.js"
new file mode 100644
index 0000000..319a06e
--- /dev/null
+++ "b/JooKangsan/10\354\243\274\354\260\250/215_Kth_Largest_Element_in_an_Array.js"
@@ -0,0 +1,29 @@
+/**
+ * @param {number[]} nums
+ * @param {number} k
+ * @return {number}
+ */
+var findKthLargest = function(nums, k) {
+  let [min, max] = nums.reduce(([min, max], num) => 
+      [Math.min(min, num), Math.max(max, num)], 
+      [Infinity, -Infinity]
+  );
+  
+  const offset = min >= 0 ? 0 : -min;
+  const count = new Array(max + 1 + offset).fill(0);
+  
+  for(let num of nums) {
+      count[num + offset]++;
+  }
+  
+  let kthLargest;
+  for(let i = count.length - 1; i >= 0; i--) {
+      k -= count[i];
+      if(k <= 0) {
+          kthLargest = i - offset;
+          break;
+      }
+  }
+  
+  return kthLargest;
+};
\ No newline at end of file
diff --git "a/JooKangsan/10\354\243\274\354\260\250/235_Lowest_Common_Ancestor_of_a_Binary_Search_Tree.js" "b/JooKangsan/10\354\243\274\354\260\250/235_Lowest_Common_Ancestor_of_a_Binary_Search_Tree.js"
new file mode 100644
index 0000000..8ae1d92
--- /dev/null
+++ "b/JooKangsan/10\354\243\274\354\260\250/235_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) {
+  let min = Math.min(p.val, q.val)
+  let max = Math.max(p.val, q.val)
+
+  if(min > root.val) {
+      return lowestCommonAncestor(root.right, p, q)
+  } else if(max < root.val) {
+      return lowestCommonAncestor(root.left, p, q)
+  } else {
+      return root
+  }
+};
\ No newline at end of file
diff --git "a/JooKangsan/10\354\243\274\354\260\250/56_Merge_Intervals.js" "b/JooKangsan/10\354\243\274\354\260\250/56_Merge_Intervals.js"
new file mode 100644
index 0000000..bfc6c78
--- /dev/null
+++ "b/JooKangsan/10\354\243\274\354\260\250/56_Merge_Intervals.js"
@@ -0,0 +1,18 @@
+/**
+ * @param {number[][]} intervals
+ * @return {number[][]}
+ */
+var merge = function (intervals) {
+  intervals.sort((a, b) => a[0] - b[0]);
+
+  for (let i = 1; i < intervals.length; i++) {
+    if (intervals[i][0] <= intervals[i - 1][1]) {
+      intervals[i][1] = Math.max(intervals[i][1], intervals[i - 1][1]);
+      intervals[i][0] = intervals[i - 1][0];
+      intervals.splice(i - 1, 1);
+      i--;
+    }
+  }
+
+  return intervals;
+};
diff --git a/JooKangsan/121_Best_Time_to_Buy_and_Sell_Stock.js "b/JooKangsan/1\354\243\274\354\260\250/121_Best_Time_to_Buy_and_Sell_Stock.js"
similarity index 100%
rename from JooKangsan/121_Best_Time_to_Buy_and_Sell_Stock.js
rename to "JooKangsan/1\354\243\274\354\260\250/121_Best_Time_to_Buy_and_Sell_Stock.js"
diff --git a/JooKangsan/15_3Sum.js "b/JooKangsan/1\354\243\274\354\260\250/15_3Sum.js"
similarity index 100%
rename from JooKangsan/15_3Sum.js
rename to "JooKangsan/1\354\243\274\354\260\250/15_3Sum.js"
diff --git a/JooKangsan/217_Contains_Duplicate.js "b/JooKangsan/1\354\243\274\354\260\250/217_Contains_Duplicate.js"
similarity index 100%
rename from JooKangsan/217_Contains_Duplicate.js
rename to "JooKangsan/1\354\243\274\354\260\250/217_Contains_Duplicate.js"
diff --git a/JooKangsan/268_Missing_Number.js "b/JooKangsan/1\354\243\274\354\260\250/268_Missing_Number.js"
similarity index 100%
rename from JooKangsan/268_Missing_Number.js
rename to "JooKangsan/1\354\243\274\354\260\250/268_Missing_Number.js"
diff --git a/JooKangsan/Meeting Schedule.js "b/JooKangsan/1\354\243\274\354\260\250/Meeting Schedule.js"
similarity index 100%
rename from JooKangsan/Meeting Schedule.js
rename to "JooKangsan/1\354\243\274\354\260\250/Meeting Schedule.js"
diff --git a/JooKangsan/100_Same_Tree.js "b/JooKangsan/2\354\243\274\354\260\250/100_Same_Tree.js"
similarity index 100%
rename from JooKangsan/100_Same_Tree.js
rename to "JooKangsan/2\354\243\274\354\260\250/100_Same_Tree.js"
diff --git a/JooKangsan/191_Number_of_1_Bits.js "b/JooKangsan/2\354\243\274\354\260\250/191_Number_of_1_Bits.js"
similarity index 100%
rename from JooKangsan/191_Number_of_1_Bits.js
rename to "JooKangsan/2\354\243\274\354\260\250/191_Number_of_1_Bits.js"
diff --git a/JooKangsan/238_Product_of_Array_Except_Self.js "b/JooKangsan/2\354\243\274\354\260\250/238_Product_of_Array_Except_Self.js"
similarity index 100%
rename from JooKangsan/238_Product_of_Array_Except_Self.js
rename to "JooKangsan/2\354\243\274\354\260\250/238_Product_of_Array_Except_Self.js"
diff --git a/JooKangsan/242_Valid_Anagram.js "b/JooKangsan/2\354\243\274\354\260\250/242_Valid_Anagram.js"
similarity index 100%
rename from JooKangsan/242_Valid_Anagram.js
rename to "JooKangsan/2\354\243\274\354\260\250/242_Valid_Anagram.js"
diff --git a/JooKangsan/746_Min_Cost_Climbing_Stairs.js "b/JooKangsan/2\354\243\274\354\260\250/746_Min_Cost_Climbing_Stairs.js"
similarity index 100%
rename from JooKangsan/746_Min_Cost_Climbing_Stairs.js
rename to "JooKangsan/2\354\243\274\354\260\250/746_Min_Cost_Climbing_Stairs.js"
diff --git a/JooKangsan/125_Valid_Palindrome.js "b/JooKangsan/3\354\243\274\354\260\250/125_Valid_Palindrome.js"
similarity index 100%
rename from JooKangsan/125_Valid_Palindrome.js
rename to "JooKangsan/3\354\243\274\354\260\250/125_Valid_Palindrome.js"
diff --git a/JooKangsan/190_Reverse_Bits.js "b/JooKangsan/3\354\243\274\354\260\250/190_Reverse_Bits.js"
similarity index 100%
rename from JooKangsan/190_Reverse_Bits.js
rename to "JooKangsan/3\354\243\274\354\260\250/190_Reverse_Bits.js"
diff --git a/JooKangsan/206_Reverse_Linked_List.js "b/JooKangsan/3\354\243\274\354\260\250/206_Reverse_Linked_List.js"
similarity index 100%
rename from JooKangsan/206_Reverse_Linked_List.js
rename to "JooKangsan/3\354\243\274\354\260\250/206_Reverse_Linked_List.js"
diff --git a/JooKangsan/322_Coin_Change.js "b/JooKangsan/3\354\243\274\354\260\250/322_Coin_Change.js"
similarity index 100%
rename from JooKangsan/322_Coin_Change.js
rename to "JooKangsan/3\354\243\274\354\260\250/322_Coin_Change.js"
diff --git a/JooKangsan/49_Group_Anagrams.js "b/JooKangsan/3\354\243\274\354\260\250/49_Group_Anagrams.js"
similarity index 100%
rename from JooKangsan/49_Group_Anagrams.js
rename to "JooKangsan/3\354\243\274\354\260\250/49_Group_Anagrams.js"
diff --git a/JooKangsan/104_Maximum_Depth_of_Binary_Tree.js "b/JooKangsan/4\354\243\274\354\260\250/104_Maximum_Depth_of_Binary_Tree.js"
similarity index 100%
rename from JooKangsan/104_Maximum_Depth_of_Binary_Tree.js
rename to "JooKangsan/4\354\243\274\354\260\250/104_Maximum_Depth_of_Binary_Tree.js"
diff --git a/JooKangsan/141_Linked_List_Cycle.js "b/JooKangsan/4\354\243\274\354\260\250/141_Linked_List_Cycle.js"
similarity index 100%
rename from JooKangsan/141_Linked_List_Cycle.js
rename to "JooKangsan/4\354\243\274\354\260\250/141_Linked_List_Cycle.js"
diff --git a/JooKangsan/1_Two_Sum.js "b/JooKangsan/4\354\243\274\354\260\250/1_Two_Sum.js"
similarity index 100%
rename from JooKangsan/1_Two_Sum.js
rename to "JooKangsan/4\354\243\274\354\260\250/1_Two_Sum.js"
diff --git a/JooKangsan/202_Happy_Number.js "b/JooKangsan/4\354\243\274\354\260\250/202_Happy_Number.js"
similarity index 100%
rename from JooKangsan/202_Happy_Number.js
rename to "JooKangsan/4\354\243\274\354\260\250/202_Happy_Number.js"
diff --git a/JooKangsan/20_Valid_Parentheses.js "b/JooKangsan/4\354\243\274\354\260\250/20_Valid_Parentheses.js"
similarity index 100%
rename from JooKangsan/20_Valid_Parentheses.js
rename to "JooKangsan/4\354\243\274\354\260\250/20_Valid_Parentheses.js"
diff --git "a/JooKangsan/5\354\243\274\354\260\250/1046_Last_Stone_Weight.js" "b/JooKangsan/5\354\243\274\354\260\250/1046_Last_Stone_Weight.js"
new file mode 100644
index 0000000..a8e11c3
--- /dev/null
+++ "b/JooKangsan/5\354\243\274\354\260\250/1046_Last_Stone_Weight.js"
@@ -0,0 +1,15 @@
+/**
+ * @param {number[]} stones
+ * @return {number}
+ */
+var lastStoneWeight = function (stones) {
+  while (stones.length > 1) {
+    stones.sort((a, b) => b - a);
+    const first = stones.shift();
+    const second = stones.shift();
+    if (first !== second) {
+      stones.push(first - second);
+    }
+  }
+  return stones.length === 0 ? 0 : stones[0];
+};
diff --git "a/JooKangsan/5\354\243\274\354\260\250/21_Merge_Two_Sorted_Lists.js" "b/JooKangsan/5\354\243\274\354\260\250/21_Merge_Two_Sorted_Lists.js"
new file mode 100644
index 0000000..37aec34
--- /dev/null
+++ "b/JooKangsan/5\354\243\274\354\260\250/21_Merge_Two_Sorted_Lists.js"
@@ -0,0 +1,23 @@
+/**
+ * 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 == null) return list2;
+  if (list2 == null) return list1;
+  if (list1.val <= list2.val) {
+    list1.next = mergeTwoLists(list1.next, list2);
+    return list1;
+  } else {
+    list2.next = mergeTwoLists(list1, list2.next);
+    return list2;
+  }
+};
diff --git "a/JooKangsan/5\354\243\274\354\260\250/338_Counting_Bits.js" "b/JooKangsan/5\354\243\274\354\260\250/338_Counting_Bits.js"
new file mode 100644
index 0000000..128e1c1
--- /dev/null
+++ "b/JooKangsan/5\354\243\274\354\260\250/338_Counting_Bits.js"
@@ -0,0 +1,13 @@
+/**
+ * @param {number} n
+ * @return {number[]}
+ */
+var countBits = function (n) {
+  const ans = new Array(n + 1).fill(0);
+
+  for (let i = 1; i <= n; i++) {
+    ans[i] = ans[Math.floor(i / 2)] + (i % 2);
+  }
+
+  return ans;
+};
diff --git "a/JooKangsan/5\354\243\274\354\260\250/48_Rotate_Image.js" "b/JooKangsan/5\354\243\274\354\260\250/48_Rotate_Image.js"
new file mode 100644
index 0000000..aec7e05
--- /dev/null
+++ "b/JooKangsan/5\354\243\274\354\260\250/48_Rotate_Image.js"
@@ -0,0 +1,14 @@
+/**
+ * @param {number[][]} matrix
+ * @return {void} Do not return anything, modify matrix in-place instead.
+ */
+var rotate = function (matrix) {
+  for (let i = 0; i < matrix.length; i++) {
+    for (let j = i + 1; j < matrix.length; j++) {
+      [matrix[i][j], matrix[j][i]] = [matrix[j][i], matrix[i][j]];
+    }
+  }
+  for (let i = 0; i < matrix.length; i++) {
+    matrix[i].reverse();
+  }
+};
diff --git "a/JooKangsan/5\354\243\274\354\260\250/70_Climbing_Stairs.js" "b/JooKangsan/5\354\243\274\354\260\250/70_Climbing_Stairs.js"
new file mode 100644
index 0000000..93ddac8
--- /dev/null
+++ "b/JooKangsan/5\354\243\274\354\260\250/70_Climbing_Stairs.js"
@@ -0,0 +1,14 @@
+/**
+ * @param {number} n
+ * @return {number}
+ */
+var climbStairs = function (n) {
+  if (n <= 2) return n;
+  const step = new Array(n + 1).fill(0);
+  step[1] = 1;
+  step[2] = 2;
+  for (let i = 3; i <= n; i++) {
+    step[i] = step[i - 1] + step[i - 2];
+  }
+  return step[n];
+};
diff --git "a/JooKangsan/6\354\243\274\354\260\250/ 703_Kth_Largest_Element_in_a_Stream.js" "b/JooKangsan/6\354\243\274\354\260\250/ 703_Kth_Largest_Element_in_a_Stream.js"
new file mode 100644
index 0000000..7f92245
--- /dev/null
+++ "b/JooKangsan/6\354\243\274\354\260\250/ 703_Kth_Largest_Element_in_a_Stream.js"	
@@ -0,0 +1,63 @@
+/**
+ * @param {number} k
+ * @param {number[]} nums
+ */
+var KthLargest = function(k, nums) {
+  this.k = k;
+  this.h = [];
+
+  // populate the array
+  const limit = Math.min(this.k, nums.length);
+  for(let i = 0; i < limit; i++) {
+      this.h.push(nums[i]);
+  }
+  this.heapifyBottomUp();
+  // add remaining elements
+  for(let i = k; i < nums.length; i++) {
+      this.add(nums[i]);
+  }
+};
+
+KthLargest.prototype.heapifyBottomUp = function() {
+  const firstLeafAt = Math.floor(this.h.length/2);
+  for(let i = firstLeafAt - 1; i >= 0; i--) {
+      this.heapify(i);
+  }
+}
+
+KthLargest.prototype.heapify = function(i) {
+  const l = 2*i + 1;
+  const r = 2*i + 2;
+
+  let min = i;
+
+  if(l < this.h.length && this.h[l] < this.h[min]) {
+      min = l
+  }
+
+  if(r < this.h.length && this.h[r] < this.h[min]) {
+      min = r;
+  }
+
+  if(min != i) {
+      [this.h[i], this.h[min]] = [this.h[min], this.h[i]];
+      this.heapify(min)
+  }
+};
+
+/** 
+* @param {number} val
+* @return {number}
+*/
+KthLargest.prototype.add = function(val) {
+  if(this.h.length < this.k) { // heap is not full
+      this.h.push(val);
+      this.heapifyBottomUp();
+  } else {
+      if(val > this.h[0]) {
+          this.h[0] = val;
+          this.heapify(0)
+      }
+  }
+  return this.h[0];
+};
\ No newline at end of file
diff --git "a/JooKangsan/6\354\243\274\354\260\250/198_House_Robber.js" "b/JooKangsan/6\354\243\274\354\260\250/198_House_Robber.js"
new file mode 100644
index 0000000..a4443db
--- /dev/null
+++ "b/JooKangsan/6\354\243\274\354\260\250/198_House_Robber.js"
@@ -0,0 +1,18 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var rob = function (nums) {
+  let n = nums.length;
+  if (n === 0) return 0;
+  if (n === 1) return nums[0];
+
+  let dp = new Array(n + 1).fill(0);
+  dp[1] = nums[0];
+
+  for (let i = 2; i <= n; i++) {
+    dp[i] = Math.max(dp[i - 1], dp[i - 2] + nums[i - 1]);
+  }
+
+  return dp[n];
+};
diff --git "a/JooKangsan/6\354\243\274\354\260\250/271_Encode_and_Decode_Strings.js" "b/JooKangsan/6\354\243\274\354\260\250/271_Encode_and_Decode_Strings.js"
new file mode 100644
index 0000000..0bf15a0
--- /dev/null
+++ "b/JooKangsan/6\354\243\274\354\260\250/271_Encode_and_Decode_Strings.js"
@@ -0,0 +1,27 @@
+class Solution {
+  /**
+   * @param {string[]} strs
+   * @returns {string}
+   */
+  encode(strs) {
+    return strs.map((s) => `${s.length}#${s}`).join("");
+  }
+
+  /**
+   * @param {string} str
+   * @returns {string[]}
+   */
+  decode(str) {
+    let i = 0;
+    const result = [];
+
+    while (i < str.length) {
+      let j = str.indexOf("#", i);
+      let length = parseInt(str.slice(i, j), 10);
+      result.push(str.slice(j + 1, j + 1 + length));
+      i = j + 1 + length;
+    }
+
+    return result;
+  }
+}
diff --git "a/JooKangsan/6\354\243\274\354\260\250/66_Plus_One.js" "b/JooKangsan/6\354\243\274\354\260\250/66_Plus_One.js"
new file mode 100644
index 0000000..81c2f98
--- /dev/null
+++ "b/JooKangsan/6\354\243\274\354\260\250/66_Plus_One.js"
@@ -0,0 +1,8 @@
+/**
+ * @param {number[]} digits
+ * @return {number[]}
+ */
+var plusOne = function (digits) {
+  const join = BigInt(digits.join("")) + 1n;
+  return join.toString().split("").map(Number);
+};
diff --git "a/JooKangsan/6\354\243\274\354\260\250/704_Binary_Search.js" "b/JooKangsan/6\354\243\274\354\260\250/704_Binary_Search.js"
new file mode 100644
index 0000000..3f0a314
--- /dev/null
+++ "b/JooKangsan/6\354\243\274\354\260\250/704_Binary_Search.js"
@@ -0,0 +1,22 @@
+/**
+ * @param {number[]} nums
+ * @param {number} target
+ * @return {number}
+ */
+var search = function(nums, target) {
+  let left = 0;
+  let right = nums.length - 1;
+  while (left <= right) {
+      const center = Math.floor((left + right) / 2);
+
+      if (nums[center] === target) {
+          return center;
+      } else if (nums[center] < target) {
+          left = center + 1;
+      } else {
+          right = center - 1;
+      }
+  }
+
+  return -1;
+}
\ No newline at end of file
diff --git "a/JooKangsan/7\354\243\274\354\260\250/110_Balanced_Binary_Tree.js" "b/JooKangsan/7\354\243\274\354\260\250/110_Balanced_Binary_Tree.js"
new file mode 100644
index 0000000..8158c2e
--- /dev/null
+++ "b/JooKangsan/7\354\243\274\354\260\250/110_Balanced_Binary_Tree.js"
@@ -0,0 +1,38 @@
+/**
+ * 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}
+ */
+/**
+ * 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)
+ * }
+ */
+var isBalanced = function (root) {
+  function checkHeight(node) {
+    if (!node) return 0;
+
+    const leftHeight = checkHeight(node.left);
+
+    if (leftHeight === -1) return -1;
+
+    const rightHeight = checkHeight(node.right);
+
+    if (rightHeight === -1) return -1;
+
+    if (Math.abs(leftHeight - rightHeight) > 1) return -1;
+
+    return Math.max(leftHeight, rightHeight) + 1;
+  }
+  return checkHeight(root) !== -1;
+};
diff --git "a/JooKangsan/7\354\243\274\354\260\250/136_Single_Numver.js" "b/JooKangsan/7\354\243\274\354\260\250/136_Single_Numver.js"
new file mode 100644
index 0000000..e2bed4b
--- /dev/null
+++ "b/JooKangsan/7\354\243\274\354\260\250/136_Single_Numver.js"
@@ -0,0 +1,10 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var singleNumber = function (nums) {
+  nums.sort((a, b) => a - b);
+  for (let i = 0; i < nums.length; i += 2) {
+    if (nums[i] !== nums[i + 1]) return nums[i];
+  }
+};
diff --git "a/JooKangsan/7\354\243\274\354\260\250/155_Min_Stack.js" "b/JooKangsan/7\354\243\274\354\260\250/155_Min_Stack.js"
new file mode 100644
index 0000000..1702683
--- /dev/null
+++ "b/JooKangsan/7\354\243\274\354\260\250/155_Min_Stack.js"
@@ -0,0 +1,33 @@
+class MinStack {
+  constructor() {
+      this.stack = [];
+      this.minStack = [];
+  }
+  push(val) {
+      this.stack.push(val);
+      
+      if (this.minStack.length === 0 || val <= this.getMin()) {
+          this.minStack.push(val);
+      }
+  }
+  pop() {
+      if (this.stack.pop() === this.getMin()) {
+          this.minStack.pop();
+      }
+  }
+  top() {
+      return this.stack[this.stack.length - 1];
+  }
+  getMin() {
+      return this.minStack[this.minStack.length - 1];
+  }
+}
+
+/** 
+* 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()
+*/
diff --git "a/JooKangsan/7\354\243\274\354\260\250/54_Spiral_Matrix.js" "b/JooKangsan/7\354\243\274\354\260\250/54_Spiral_Matrix.js"
new file mode 100644
index 0000000..56b582d
--- /dev/null
+++ "b/JooKangsan/7\354\243\274\354\260\250/54_Spiral_Matrix.js"
@@ -0,0 +1,27 @@
+/**
+ * @param {number[][]} matrix
+ * @return {number[]}
+ */
+var spiralOrder = function(matrix) {
+  const result = [];
+  
+  while(matrix.length > 0) {
+      if(matrix.length > 0) {
+          result.push(...matrix.shift());
+      }
+      for(let i = 0; i < matrix.length; i++) {
+          if(matrix[i].length > 0) {
+              result.push(matrix[i].pop());
+          }
+      }
+      if(matrix.length > 0) {
+          result.push(...matrix.pop().reverse());
+      }
+      for(let i = matrix.length - 1; i >= 0; i--) {
+          if(matrix[i].length > 0) {
+              result.push(matrix[i].shift());
+          }
+      }
+  }
+  return result;
+}
\ No newline at end of file
diff --git "a/JooKangsan/7\354\243\274\354\260\250/973_K_Closest_Points_to_Origin.js" "b/JooKangsan/7\354\243\274\354\260\250/973_K_Closest_Points_to_Origin.js"
new file mode 100644
index 0000000..1817da2
--- /dev/null
+++ "b/JooKangsan/7\354\243\274\354\260\250/973_K_Closest_Points_to_Origin.js"
@@ -0,0 +1,17 @@
+/**
+ * @param {number[][]} points
+ * @param {number} k
+ * @return {number[][]}
+ */
+var kClosest = function(points, k) {
+  const result = [];
+  
+  for(let i = 0; i < points.length; i++) {
+      result.push([
+          points[i][0]**2 + points[i][1]**2,
+          i  
+      ]);
+  }
+  result.sort((a, b) => a[0] - b[0]);
+  return result.slice(0, k).map(item => points[item[1]]);
+}; 
\ No newline at end of file
diff --git "a/JooKangsan/8\354\243\274\354\260\250/128_Longest_Consecutive_Sequence.js" "b/JooKangsan/8\354\243\274\354\260\250/128_Longest_Consecutive_Sequence.js"
new file mode 100644
index 0000000..31eafb4
--- /dev/null
+++ "b/JooKangsan/8\354\243\274\354\260\250/128_Longest_Consecutive_Sequence.js"
@@ -0,0 +1,20 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var longestConsecutive = function(nums) {
+  const numSet = new Set(nums);
+let longestStreak = 0;
+for (const num of numSet) {
+if (!numSet.has(num - 1)) {
+  let currentNum = num;
+  let currentStreak = 1;
+  while (numSet.has(currentNum + 1)) {
+    currentNum += 1;
+    currentStreak += 1;
+  }
+  longestStreak = Math.max(longestStreak, currentStreak);
+}
+}
+return longestStreak;
+};
diff --git "a/JooKangsan/8\354\243\274\354\260\250/208_Implement_Trie(PrefixTree).js" "b/JooKangsan/8\354\243\274\354\260\250/208_Implement_Trie(PrefixTree).js"
new file mode 100644
index 0000000..f41c597
--- /dev/null
+++ "b/JooKangsan/8\354\243\274\354\260\250/208_Implement_Trie(PrefixTree).js"
@@ -0,0 +1,61 @@
+var Trie = function() {
+  this.root = {
+      children : {},
+      isEnd : false
+  }
+};
+
+/** 
+* @param {string} word
+* @return {void}
+*/
+Trie.prototype.insert = function(word) {
+  let node = this.root;
+  
+  for(let char of word) {
+      if(!node.children[char]) {
+          node.children[char] = {
+              children: {},
+              isEnd: false
+          };
+      }
+      node = node.children[char];
+  }
+  
+  node.isEnd = true;
+};
+
+/** 
+* @param {string} word
+* @return {boolean}
+*/
+Trie.prototype.search = function(word) {
+  let node = this.root;
+  
+  // 단어의 각 문자에 대해
+  for(let char of word) {
+      if(!node.children[char]) {
+          return false;
+      }
+      node = node.children[char];
+  }
+
+  return node.isEnd;
+};
+
+/** 
+* @param {string} prefix
+* @return {boolean}
+*/
+Trie.prototype.startsWith = function(prefix) {
+  let node = this.root;
+
+  for(let char of prefix) {
+      if(!node.children[char]) {
+          return false;
+      }
+      node = node.children[char];
+  }
+  
+  return true;
+};
\ No newline at end of file
diff --git "a/JooKangsan/8\354\243\274\354\260\250/226_Invert_Binary_Tree.js" "b/JooKangsan/8\354\243\274\354\260\250/226_Invert_Binary_Tree.js"
new file mode 100644
index 0000000..c4e8981
--- /dev/null
+++ "b/JooKangsan/8\354\243\274\354\260\250/226_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 === null) return null;
+
+  let temp = root.left;
+
+  root.left = invertTree(root.right);
+  root.right = invertTree(temp);
+
+  return root;
+};
diff --git "a/JooKangsan/8\354\243\274\354\260\250/371_Sum_of_Two_Integers.js" "b/JooKangsan/8\354\243\274\354\260\250/371_Sum_of_Two_Integers.js"
new file mode 100644
index 0000000..ce07cff
--- /dev/null
+++ "b/JooKangsan/8\354\243\274\354\260\250/371_Sum_of_Two_Integers.js"
@@ -0,0 +1,13 @@
+/**
+ * @param {number} a
+ * @param {number} b
+ * @return {number}
+ */
+var getSum = function(a, b) {
+  while (b !== 0) {
+      let carry = a & b;
+      a = a ^ b;
+      b = carry << 1;
+  }
+  return a;
+};
\ No newline at end of file
diff --git "a/JooKangsan/8\354\243\274\354\260\250/543_Diameter_of_Binary_Tree.js" "b/JooKangsan/8\354\243\274\354\260\250/543_Diameter_of_Binary_Tree.js"
new file mode 100644
index 0000000..7068f26
--- /dev/null
+++ "b/JooKangsan/8\354\243\274\354\260\250/543_Diameter_of_Binary_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
+ * @return {number}
+ */
+var diameterOfBinaryTree = function(root) {
+  let maxDiameter = 0;
+
+function getHeight(node) {
+  if (!node) return -1;
+
+  let leftHeight = getHeight(node.left);
+  let rightHeight = getHeight(node.right);
+
+  maxDiameter = Math.max(maxDiameter, leftHeight + rightHeight + 2);
+
+  return Math.max(leftHeight, rightHeight) + 1;
+}
+
+getHeight(root);
+
+return maxDiameter;
+};
\ No newline at end of file
diff --git "a/JooKangsan/9\354\243\274\354\260\250/102_Binary Tree_Level_Order_Traversal.js" "b/JooKangsan/9\354\243\274\354\260\250/102_Binary Tree_Level_Order_Traversal.js"
new file mode 100644
index 0000000..4d4c116
--- /dev/null
+++ "b/JooKangsan/9\354\243\274\354\260\250/102_Binary Tree_Level_Order_Traversal.js"	
@@ -0,0 +1,35 @@
+/**
+ * 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 queue = [root];
+  
+  while (queue.length > 0) {
+      const levelSize = queue.length;
+      const currentLevel = [];
+      
+      for (let i = 0; i < levelSize; i++) {
+          const node = queue.shift();
+          currentLevel.push(node.val);
+          
+          if (node.left) queue.push(node.left);
+          if (node.right) queue.push(node.right);
+      }
+      
+      result.push(currentLevel);
+  }
+  
+  return result;
+};
\ No newline at end of file
diff --git "a/JooKangsan/9\354\243\274\354\260\250/150_Evaluate_Reverse_Polish_Notation.js" "b/JooKangsan/9\354\243\274\354\260\250/150_Evaluate_Reverse_Polish_Notation.js"
new file mode 100644
index 0000000..19ea93e
--- /dev/null
+++ "b/JooKangsan/9\354\243\274\354\260\250/150_Evaluate_Reverse_Polish_Notation.js"
@@ -0,0 +1,38 @@
+/**
+ * @param {string[]} tokens
+ * @return {number}
+ */
+var evalRPN = function (tokens) {
+  while (tokens.length > 1) {
+    for (let i = 0; i < tokens.length; i++) {
+      if (["+", "-", "*", "/"].includes(tokens[i])) {
+        const num1 = Number(tokens[i - 2]);
+        const num2 = Number(tokens[i - 1]);
+        const operator = tokens[i];
+        let result;
+
+        switch (operator) {
+          case "+":
+            result = num1 + num2;
+            break;
+          case "-":
+            result = num1 - num2;
+            break;
+          case "*":
+            result = num1 * num2;
+            break;
+          case "/":
+            result =
+              num1 / num2 > 0
+                ? Math.floor(num1 / num2)
+                : Math.ceil(num1 / num2);
+            break;
+        }
+
+        tokens.splice(i - 2, 3, result.toString());
+        break;
+      }
+    }
+  }
+  return Number(tokens[0]);
+};
diff --git "a/JooKangsan/9\354\243\274\354\260\250/203_House_Robber_II.js" "b/JooKangsan/9\354\243\274\354\260\250/203_House_Robber_II.js"
new file mode 100644
index 0000000..397ea13
--- /dev/null
+++ "b/JooKangsan/9\354\243\274\354\260\250/203_House_Robber_II.js"
@@ -0,0 +1,32 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var rob = function (nums) {
+  let n = nums.length;
+  if (n === 0) return 0;
+  if (n === 1) return nums[0];
+  if (n === 2) return Math.max(nums[0], nums[1]);
+
+  let firstCase = [...nums];
+  firstCase.pop();
+  let first = robHelper(firstCase);
+
+  let secondCase = [...nums];
+  secondCase.shift();
+  let second = robHelper(secondCase);
+
+  return Math.max(first, second);
+};
+
+function robHelper(houses) {
+  let n = houses.length;
+  let dp = new Array(n).fill(0);
+  dp[0] = houses[0];
+  dp[1] = Math.max(houses[0], houses[1]);
+
+  for (let i = 2; i < n; i++) {
+    dp[i] = Math.max(dp[i - 1], dp[i - 2] + houses[i]);
+  }
+  return dp[n - 1];
+}
diff --git "a/JooKangsan/9\354\243\274\354\260\250/572_Subtree_of_Another_Tree.js" "b/JooKangsan/9\354\243\274\354\260\250/572_Subtree_of_Another_Tree.js"
new file mode 100644
index 0000000..a1c3b9d
--- /dev/null
+++ "b/JooKangsan/9\354\243\274\354\260\250/572_Subtree_of_Another_Tree.js"
@@ -0,0 +1,29 @@
+/**
+ * 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 (!subRoot) return true;
+  if (!root) return false;
+  
+  const isSameTree = (tree1, tree2) => {
+      if (!tree1 && !tree2) return true;
+      if (!tree1 || !tree2) return false;
+      if (tree1.val !== tree2.val) return false;
+      return isSameTree(tree1.left, tree2.left) && 
+             isSameTree(tree1.right, tree2.right);
+  };
+  
+  return isSameTree(root, subRoot) || 
+         isSubtree(root.left, subRoot) || 
+         isSubtree(root.right, subRoot);
+};
\ No newline at end of file