class Solution {
public:void setZeroes(vector<vector<int>>& matrix) {int m = matrix.size();int n = matrix[0].size();int flag_col0 = false, flag_row0 = false;//先记录第一行和第一列是否有零for (int i = 0; i < m; i++) {if (!matrix[i][0]) {flag_col0 = true;}}for (int j = 0; j < n; j++) {if (!matrix[0][j]) {flag_row0 = true;}}for (int i = 1; i < m; i++) {for (int j = 1; j < n; j++) {if (!matrix[i][j]) {matrix[i][0] = matrix[0][j] = 0;//用第一行和第一列去记录}}}for (int i = 1; i < m; i++) {for (int j = 1; j < n; j++) {if (!matrix[i][0] || !matrix[0][j]) {matrix[i][j] = 0;//用第一行和第一列的0去更新其他所有行列}}}//最后根据开头标记更新第一行和第一列if (flag_col0) {for (int i = 0; i < m; i++) {matrix[i][0] = 0;}}if (flag_row0) {for (int j = 0; j < n; j++) {matrix[0][j] = 0;}}}
};
