Done arr 1

diag_ele_matrix_498.py

@@ -0,0 +1,26 @@
+#O(mn) sc o(min(m,n))
+class Solution:
+    def findDiagonalOrder(self, mat: List[List[int]]) -> List[int]:
+        q = deque([(0, 0)])
+        rows, cols = len(mat), len(mat[0])
+        ans = []
+        reverse = False
+
+        while q:
+            level = []
+            for _ in range(len(q)):
+                row, col = q.popleft()
+                level.append(mat[row][col])
+
+                if col == 0 and row + 1 < rows:
+                    q.append((row + 1, col))
+                if col + 1 < cols:
+                    q.append((row, col + 1))
+
+            if reverse:
+                ans.extend(level[::-1])
+            else:
+                ans.extend(level)
+            reverse = not reverse
+
+        return ans

product_except_self_238.py

@@ -0,0 +1,17 @@
+class Solution:
+    def productExceptSelf(self, nums: List[int]) -> List[int]:
+        n = len(nums)
+        res = [1] * n
+        prefix_prod = 1
+        suffix_prod = 1
+
+        for i in range(n):
+            res[i] = res[i] * prefix_prod
+            prefix_prod = prefix_prod * nums[i]
+
+        for i in range(n - 1, -1, -1):
+            res[i] = res[i] * suffix_prod
+            suffix_prod = suffix_prod * nums[i]
+        return res
+
+