Maximal Rectangle [LeetCode]

Problem Description: Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing all ones and return its area.

Basic idea: To increas one dimension by one, then calculate the maximum of other dimension every time.

 class Solution {
 public:
     int maximalRectangle(vector<vector<char> > &matrix) {
         // Note: The Solution object is instantiated only once and is reused by each test case.
         if(matrix.size() ==  || matrix[].size() == )
             return ;
         int max_area = ;
         int row = matrix.size();
         int column = matrix[].size();
         for(int i = ; i < row; i ++) {
             for( int j = ; j < column; j ++) {
                 if (matrix[i][j] == '')
                     continue;

                 int tmp_area = ;
                 int max_row_idx = row - ;
                 int max_column_idx = j;
                 while(max_column_idx < column){
                     int l;
                     for(l = i + ; l <= max_row_idx; l ++){
                          if (matrix[l][max_column_idx] == '')
                             break;
                     }
                     max_row_idx = l - ;
                     tmp_area = (max_row_idx - i + ) * (max_column_idx - j + );
                     if(tmp_area > max_area)
                         max_area = tmp_area;

                     //increase column
                     if ( matrix[i][max_column_idx + ] == ''){
                         max_column_idx ++;
                     }else{
                         break;
                     }
                 }

             }
         }
         return max_area;
     }
 };