Given an m x n integer matrix matrix, if an element is 0, set its entire row and column to 0's, and return the matrix.
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?
class Solution {
public void setZeroes(int[][] matrix) {
if (matrix == null || matrix.length == 0 || matrix[0].length == 0) return;
int m = matrix.length, n = matrix[0].length;
boolean row = false, col = false;
for (int i = 0; i < m; i++)
for (int j = 0; j < n; j++){
if (matrix[i][j] == 0) {
matrix[0][j] = 0;
matrix[i][0] = 0;
if (i == 0) row = true;
if (j == 0) col = true;
}
}
for (int i = 1; i < m; i++){
if (matrix[i][0] == 0){
for (int j = 1; j < n;j++)
matrix[i][j] = 0;
}
}
for (int j = 1; j < n; j++){
if (matrix[0][j] == 0){
for (int i = 1; i < m; i++)
matrix[i][j] = 0;
}
}
if (row){
for (int j = 0; j < n; j++)
matrix[0][j] = 0;
}
if (col){
for(int i = 0; i < m; i++)
matrix[i][0] = 0;
}
}
}