Completed Array-1

Problem_1.py

@@ -0,0 +1,18 @@
+# https://leetcode.com/problems/product-of-array-except-self/description/
+
+class Solution:
+    def productExceptSelf(self, nums):
+        n = len(nums)
+        result = [1]
+        for i in range(n - 1):
+            result.append(nums[i] * result[i])
+        right = 1
+        for i in range(n - 1, -1, -1):
+            result[i] = result[i] * right
+            right = nums[i] * right
+        return result
+
+
+nums = [-1,1,0,-3,3]
+sl = Solution()
+print(sl.productExceptSelf(nums))

Problem_2.py

@@ -0,0 +1,30 @@
+class Solution:
+    def findDiagonalOrder(self, mat):
+        result = []
+        rows, cols = len(mat), len(mat[0])
+        total_elements = rows * cols
+        flag = True  # True means up, False means down
+        cr, cc = 0, 0
+        while len(result) < total_elements:
+            result.append(mat[cr][cc])
+            if flag:
+                if cc == cols - 1:
+                    cr += 1
+                    flag = False
+                elif cr == 0:
+                    cc += 1
+                    flag = False
+                else:
+                    cr -= 1
+                    cc += 1
+            else:
+                if cr == rows - 1:
+                    cc += 1
+                    flag = True
+                elif cc == 0:
+                    cr += 1
+                    flag = True
+                else:
+                    cc -= 1
+                    cr += 1
+        return result

Problem_3.py

@@ -0,0 +1,36 @@
+# https://leetcode.com/problems/spiral-matrix/description/
+
+class Solution:
+    def spiralOrder(self, matrix):
+        rows, cols = len(matrix), len(matrix[0])
+        top = 0
+        right = cols - 1
+        bottom = rows - 1
+        left = 0
+        result = []
+        while top <= bottom and left <= right:
+
+            for i in range(left, right + 1, 1):
+                result.append(matrix[top][i])
+            top += 1
+
+            for i in range(top, bottom + 1, 1):
+                result.append(matrix[i][right])
+            right -= 1
+
+            if top <= bottom:
+                for i in range(right, left - 1, -1):
+                    result.append(matrix[bottom][i])
+                bottom -= 1
+
+            if left <= right:
+                for i in range(bottom, top - 1, -1):
+                    result.append(matrix[i][left])
+                left += 1
+
+        return result
+
+matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12]]
+
+sl = Solution()
+print(sl.spiralOrder(matrix))