# 73. Set Matrix Zeroes     • Time: $O(mn)$
• Space: $O(1)$
  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 class Solution { public: void setZeroes(vector>& matrix) { const int m = matrix.size(); const int n = matrix.size(); bool shouldFillFirstRow = false; bool shouldFillFirstCol = false; for (int j = 0; j < n; ++j) if (matrix[j] == 0) { shouldFillFirstRow = true; break; } for (int i = 0; i < m; ++i) if (matrix[i] == 0) { shouldFillFirstCol = true; break; } // store the information in the 1st row/col for (int i = 1; i < m; ++i) for (int j = 1; j < n; ++j) if (matrix[i][j] == 0) { matrix[i] = 0; matrix[j] = 0; } // fill 0s for the matrix except the 1st row/col for (int i = 1; i < m; ++i) for (int j = 1; j < n; ++j) if (matrix[i] == 0 || matrix[j] == 0) matrix[i][j] = 0; // fill 0s for the 1st row if needed if (shouldFillFirstRow) for (int j = 0; j < n; ++j) matrix[j] = 0; // fill 0s for the 1st col if needed if (shouldFillFirstCol) for (int i = 0; i < m; ++i) matrix[i] = 0; } }; 
  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 class Solution { public void setZeroes(int[][] matrix) { final int m = matrix.length; final int n = matrix.length; boolean shouldFillFirstRow = false; boolean shouldFillFirstCol = false; for (int j = 0; j < n; ++j) if (matrix[j] == 0) { shouldFillFirstRow = true; break; } for (int i = 0; i < m; ++i) if (matrix[i] == 0) { shouldFillFirstCol = true; break; } // store the information in the 1st row/col for (int i = 1; i < m; ++i) for (int j = 1; j < n; ++j) if (matrix[i][j] == 0) { matrix[i] = 0; matrix[j] = 0; } // fill 0s for the matrix except the 1st row/col for (int i = 1; i < m; ++i) for (int j = 1; j < n; ++j) if (matrix[i] == 0 || matrix[j] == 0) matrix[i][j] = 0; // fill 0s for the 1st row if needed if (shouldFillFirstRow) for (int j = 0; j < n; ++j) matrix[j] = 0; // fill 0s for the 1st col if needed if (shouldFillFirstCol) for (int i = 0; i < m; ++i) matrix[i] = 0; } } 
  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 class Solution: def setZeroes(self, matrix: List[List[int]]) -> None: m = len(matrix) n = len(matrix) shouldFillFirstRow = 0 in matrix shouldFillFirstCol = 0 in list(zip(*matrix)) # store the information in the 1st row/col for i in range(1, m): for j in range(1, n): if matrix[i][j] == 0: matrix[i] = 0 matrix[j] = 0 # fill 0s for the matrix except the 1st row/col for i in range(1, m): for j in range(1, n): if matrix[i] == 0 or matrix[j] == 0: matrix[i][j] = 0 # fill 0s for the 1st row if needed if shouldFillFirstRow: matrix =  * n # fill 0s for the 1st col if needed if shouldFillFirstCol: for row in matrix: row = 0