Leetcode#73 Set Matrix Zeroes

原题地址

用矩形的第一行和第一列充当mask

代码：

 void setZeroes(vector<vector<int> > &matrix) {
         if (matrix.empty() || matrix[].empty()) return;

         bool firstRow = false;
         bool firstCol = false;
         int m = matrix.size();
         int n = matrix[].size();

         for (int i = ; i < m; i++)
             if (matrix[i][] == ) {
                 firstCol = true;
                 break;
             }

         for (int j = ; j < n; j++)
             if (matrix[][j] == ) {
                 firstRow = true;
                 break;
             }

         for (int i = ; i < m; i++) {
             for (int j = ; j < n; j++) {
                 if (matrix[i][j] == ) {
                     matrix[i][] = ;
                     matrix[][j] = ;
                 }
             }
         }

         for (int i = ; i < m; i++)
             if (matrix[i][] == )
                 for (int j = ; j < n; j++)
                     matrix[i][j] = ;

         for (int j = ; j < n; j++)
             if (matrix[][j] == )
                 for (int i = ; i < m; i++)
                     matrix[i][j] = ;

         if (firstCol)
             for (int i = ; i < m; i++)
                 matrix[i][] = ;
         if (firstRow)
             for (int j = ; j < n; j++)
                 matrix[][j] = ;
 }