Set Matrix Zeroes

Author: anantkaushik

073-set-matrix-zeroes.py

@@ -0,0 +1,65 @@
+"""
+Problem Link: https://leetcode.com/problems/set-matrix-zeroes/
+
+Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in-place.
+
+Example 1:
+Input: 
+[
+  [1,1,1],
+  [1,0,1],
+  [1,1,1]
+]
+Output: 
+[
+  [1,0,1],
+  [0,0,0],
+  [1,0,1]
+]
+
+Example 2:
+Input: 
+[
+  [0,1,2,0],
+  [3,4,5,2],
+  [1,3,1,5]
+]
+Output: 
+[
+  [0,0,0,0],
+  [0,4,5,0],
+  [0,3,1,0]
+]
+
+Follow up:
+A straight forward solution using O(mn) space is probably a bad idea.
+A simple improvement uses O(m + n) space, but still not the best solution.
+Could you devise a constant space solution?
+"""
+class Solution(object):
+    def setZeroes(self, matrix):
+        """
+        :type matrix: List[List[int]]
+        :rtype: void Do not return anything, modify matrix in-place instead.
+        """
+        row = len(matrix)
+        col = len(matrix[0])
+        is_col= False
+        for i in range(row):
+            if matrix[i][0] == 0:
+                is_col= True
+            for j in range(1,col):
+                if matrix[i][j] == 0:
+                    matrix[0][j] = 0
+                    matrix[i][0] = 0
+                    
+        for i in range(1,row):
+            for j in range(1,col):
+                if not matrix[i][0] or not matrix[0][j]:
+                    matrix[i][j] = 0
+        if matrix[0][0] == 0:
+            for j in range(col):
+                matrix[0][j] = 0
+        if is_col:
+            for i in range(row):
+                matrix[i][0] = 0