Completed Leetcode 54, 498 and 238

Problem3-Leetcode54.py

@@ -0,0 +1,36 @@
+#Time Complexity: O(m*n)
+#Space Complexity: O(1)
+
+class Solution(object):
+    def spiralOrder(self, matrix):
+        """
+        :type matrix: List[List[int]]
+        :rtype: List[int]
+        """
+        result = []
+        if not matrix:
+            return result
+
+        top, bottom = 0, len(matrix) - 1
+        left, right = 0, len(matrix[0]) - 1
+
+        while top <= bottom and left <= right:
+            for i in range(left, right + 1):
+                result.append(matrix[top][i])
+            top += 1
+
+            for i in range(top, bottom + 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

problem1-leetcode238.py

@@ -0,0 +1,24 @@
+#Time Complexity: O(n)
+#Space Complexity: O(n)
+
+class Solution(object):
+    def productExceptSelf(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: List[int]
+        """
+        n, runningProduct = len(nums), 1
+        leftProduct = [0] * n
+        leftProduct[0] = 1
+
+        for i in range(1, len(nums)):
+            runningProduct = runningProduct * nums[i - 1]
+            leftProduct[i] = runningProduct
+
+        runningProduct = 1
+        for i in range(n-2, -1, -1):
+            runningProduct = runningProduct * nums[i + 1]
+            leftProduct[i] = leftProduct[i] * runningProduct
+
+        return leftProduct
+

problem2-Leetcode498.py

@@ -0,0 +1,37 @@
+#Time Complexity: O(m*n)
+#Space Complexity: O(1)
+
+class Solution(object):
+    def findDiagonalOrder(self, mat):
+        """
+        :type mat: List[List[int]]
+        :rtype: List[int]
+        """
+        m, n = len(mat), len(mat[0])
+        r, c, x, flag = 0, 0, m * n, True
+        arr = []
+        for _ in range(x):
+            arr.append(mat[r][c])
+            if flag:
+                if r == 0 and c != n - 1:
+                    c += 1
+                    flag = False
+                elif c == n - 1:
+                    r += 1
+                    flag = False
+                else:
+                    r -= 1
+                    c += 1
+            else:
+                if c == 0 and r != m - 1:
+                    r += 1
+                    flag = True
+                elif r == m - 1:
+                    c += 1
+                    flag = True
+                else:
+                    r += 1
+                    c -= 1
+
+        return arr
+