From 8b34127889d7f5dacafc6718514d1713400439ba Mon Sep 17 00:00:00 2001
From: Tanya Sreenagesh <tanyasreenagesh@gmail.com>
Date: Thu, 16 Oct 2025 10:26:13 -0700
Subject: [PATCH] Submission

---
 MatrixDiagonalOrder.py | 49 ++++++++++++++++++++++++++++++++++++++++++
 MatrixSpiralOrder.py   | 43 ++++++++++++++++++++++++++++++++++++
 ProductExceptSelf.py   | 28 ++++++++++++++++++++++++
 3 files changed, 120 insertions(+)
 create mode 100644 MatrixDiagonalOrder.py
 create mode 100644 MatrixSpiralOrder.py
 create mode 100644 ProductExceptSelf.py

diff --git a/MatrixDiagonalOrder.py b/MatrixDiagonalOrder.py
new file mode 100644
index 00000000..afad11db
--- /dev/null
+++ b/MatrixDiagonalOrder.py
@@ -0,0 +1,49 @@
+# Time Complexity : O(m*n) where m is the number of rows and n is the number of columns
+# Space Complexity : O(1)
+# Did this code successfully run on Leetcode : Yes
+# Any problem you faced while coding this : No
+
+'''
+My approach:
+If the diagonal is going up, move the pointers up and to the right.
+If the diagonal is going down, move the pointers down and to the left.
+Check for edge cases where the pointers reach the boundaries of the matrix.
+'''
+class Solution:
+    def findDiagonalOrder(self, mat: List[List[int]]) -> List[int]:
+        m = len(mat)
+        n = len(mat[0])
+
+        result = []
+
+        i, j = 0, 0
+
+        up = True
+        for _ in range(m*n):
+            result.append(mat[i][j])
+            
+            if up:
+                if j == n-1: 
+                    i+=1
+                    up=False
+                elif i == 0:
+                    j+=1
+                    up=False
+                else:
+                    i-=1
+                    j+=1
+
+            # Down
+            else:
+                if i == m-1:
+                    j+=1
+                    up=True
+                elif j == 0:
+                    i+=1
+                    up=True
+                else:
+                    i+=1
+                    j-=1
+
+        return result
+    
\ No newline at end of file
diff --git a/MatrixSpiralOrder.py b/MatrixSpiralOrder.py
new file mode 100644
index 00000000..56c465c9
--- /dev/null
+++ b/MatrixSpiralOrder.py
@@ -0,0 +1,43 @@
+# Time Complexity : O(m*n) where m is the number of rows and n is the number of columns
+# Space Complexity : O(1)
+# Did this code successfully run on Leetcode : Yes
+# Any problem you faced while coding this : No
+
+'''
+My approach:
+Use four pointers to keep track of the top, bottom, left, and right boundaries of the matrix.
+Iterate through the matrix in a spiral order by moving the pointers after each side is processed.
+Sides are always processed in the same order: top, right, bottom, left.
+'''
+class Solution:
+    def spiralOrder(self, matrix: List[List[int]]) -> List[int]:
+        top, left = 0, 0
+        right = len(matrix[0])-1
+        bottom = len(matrix)-1
+
+        result = []
+
+        while top <= bottom and left <= right:
+            # Left to right
+            for i in range(left, right+1):
+                result.append(matrix[top][i])
+            top+=1
+
+            # Top to bottom
+            for j in range(top, bottom+1):
+                result.append(matrix[j][right])
+            right -=1
+
+            # Right to left
+            if top <= bottom:
+                for i in range(right, left-1, -1):
+                    result.append(matrix[bottom][i])
+                bottom -= 1
+
+            # Bottom to top
+            if left <= right:
+                for j in range(bottom, top-1, -1):
+                    result.append(matrix[j][left])
+                left+=1
+
+        return result
diff --git a/ProductExceptSelf.py b/ProductExceptSelf.py
new file mode 100644
index 00000000..6436411d
--- /dev/null
+++ b/ProductExceptSelf.py
@@ -0,0 +1,28 @@
+# Time Complexity : O(n) where n is the length of the strings
+# Space Complexity : O(1)
+# Did this code successfully run on Leetcode : Yes
+# Any problem you faced while coding this : No
+
+'''
+My approach:
+Calculate the left product for each element, then multiply it with the right running product for each element.
+'''
+class Solution:
+    def productExceptSelf(self, nums: List[int]) -> List[int]:
+        n = len(nums)
+        
+        # Starting with 0s to clarify setting first element to 1
+        leftProduct = [0] * n 
+        leftProduct[0] = 1
+        
+        # Calculate left running products
+        for i in range(1, len(nums)):
+            leftProduct[i] = leftProduct[i-1] * nums[i-1]
+
+        # Keep running counter of right product and multiply with left
+        rProduct = nums[len(nums)-1]
+        for i in range(len(nums)-2, -1, -1):
+            leftProduct[i] = rProduct * leftProduct[i]
+            rProduct = rProduct * nums[i]
+
+        return leftProduct