73.py

'''
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 1:

Input: matrix = [[1,1,1],[1,0,1],[1,1,1]]
Output: [[1,0,1],[0,0,0],[1,0,1]]

Example 2:


Input: matrix = [[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]]
 
Constraints:

m == matrix.length
n == matrix[0].length
1 <= m, n <= 200
-231 <= matrix[i][j] <= 231 - 1
 
Follow up:

A straightforward 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?
'''

# https://leetcode.com/problems/set-matrix-zeroes/

import unittest

def setZeroes(matrix):
    rows, cols = len(matrix), len(matrix[0])
    is_col = False
    for i in range(rows):
        if matrix[i][0] == 0:
            is_col = True
        for j in range(1, cols):
            if matrix[i][j] == 0:
                matrix[i][0] = 0
                matrix[0][j] = 0
    for i in range(1, rows):
        for j in range(1, cols):
            if not matrix[i][0] or not matrix[0][j]:
                matrix[i][j] = 0
    if matrix[0][0] == 0:
        for j in range(cols):
            matrix[0][j] = 0
    if is_col:
        for i in range(rows):
            matrix[i][0] = 0
    return matrix

class TestSetMatrixZeroes(unittest.TestCase):
    def test_example1(self):
        matrix = [[1, 1, 1], [1, 0, 1], [1, 1, 1]]
        expected = [[1, 0, 1], [0, 0, 0], [1, 0, 1]]
        # Call the function that solves the problem
        result = setZeroes(matrix)
        # Assert that the result matches the expected output
        self.assertEqual(result, expected)

    def test_example2(self):
        matrix = [[0, 1, 2, 0], [3, 4, 5, 2], [1, 3, 1, 5]]
        expected = [[0, 0, 0, 0], [0, 4, 5, 0], [0, 3, 1, 0]]
        # Call the function that solves the problem
        result = setZeroes(matrix)
        # Assert that the result matches the expected output
        self.assertEqual(result, expected)

if __name__ == '__main__':
    unittest.main()