Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in place.
Follow up:
Did you use extra space?
A straight forward 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?
public class Solution { public void setZeroes(int[][] matrix) { if(matrix == null){ return; } int m = matrix.length; int n = matrix[0].length; boolean row0 = false; boolean col0 = false; for(int i = 0; i < n; i++){ if(matrix[0][i] == 0){ row0 = true; break; } } for(int j = 0 ; j < m; j++){ if(matrix[j][0] == 0){ col0 = true; break; } } for(int i = 1; i < m; i++){ for(int j = 1; j < n; j++){ if(matrix[i][j] == 0){ matrix[i][0] = 0; matrix[0][j] = 0; } } } for(int i = 1; i < m; i++){ for(int j = 1; j < n; j++){ if(matrix[0][j] == 0 || matrix[i][0] == 0){ matrix[i][j] = 0; } } } if(row0 == true){ for(int i = 0; i < n; i++){ matrix[0][i] = 0; } } if(col0 == true){ for(int i = 0; i < m; i++){ matrix[i][0] = 0; } } } }