Set Matrix Zeroes — LeetCode 73 Python Solution

The problem

Given an m x n integer matrix matrix, if an element is 0, set its entire row and column to 0's. You must do it in place.

Example

Input

matrix = [[1,1,1],[1,0,1],[1,1,1]]

Output

[[1,0,1],[0,0,0],[1,0,1]]

Python solution

class Solution:
    def setZeroes(self, matrix: List[List[int]]) -> None:
        m, n = len(matrix), len(matrix[0])
        row = [False] * m
        col = [False] * n
        for i in range(m):
            for j in range(n):
                if matrix[i][j] == 0:
                    row[i] = col[j] = True
        for i in range(m):
            for j in range(n):
                if row[i] or col[j]:
                    matrix[i][j] = 0

Complexity

Pattern: Matrix and Grid

Treat a 2-D grid as a graph whose neighbours are the four adjacent cells. LeetCode 73. Set Matrix Zeroes is filed here because LeetCode tags it Matrix, which is the vocabulary this hub collects.

The matrix and grid guide has the Python template for the pattern and the 216 LeetCode problems that use it.

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