Set Matrix Zeroes
Given an m x n matrix. If an element is 0, set its entire row and column to 0. Do it in-place. Tags: Matrix
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Solution
class Solution:
def setZeroes(self, matrix: List[List[int]]) -> None:
"""
Do not return anything, modify matrix in-place instead.
"""
top_has_zero = False
for j in range(len(matrix[0])):
if matrix[0][j] == 0:
top_has_zero = True
break
# Create a marker using first row and column
# 010
# 110
# 001
for i in range(1, len(matrix)):
for j in range(len(matrix[0])):
if matrix[i][j] == 0:
matrix[i][0] = 0
matrix[0][j] = 0
# Set the zeros, backwards iterating through the row
for i in range(1, len(matrix)):
for j in range(len(matrix[0]) - 1, -1, -1):
if matrix[i][0] == 0 or matrix[0][j] == 0:
matrix[i][j] = 0
if top_has_zero:
for j in range(len(matrix[0])):
matrix[0][j] = 0