Largest area of rectangle with permutations

Given a binary grid A of size N x M consisting of 0's and 1's, find the area of the largest rectangle inside the grid such that all the cells inside the chosen rectangle should have 1 in them.

You are allowed to permutate the columns matrix i.e. you can arrange each of the column in any order in the final grid.

Please follow the sample input and explanation for more clarity.


public class Solution {
    public int solve(int[][] A) {
   
    //add column height
    for(int i=0;i<A.length;i++){
        for(int j=0;j<A[0].length;j++){
            if(i!=0 && A[i][j]!=0){
                A[i][j] = A[i][j] + A[i-1][j];    
            }
        }
    }

    //sort every row
    for(int i=0;i<A.length;i++){
        Arrays.sort(A[i]);
    }
    
    
    //final area calculate
      int maxArea = 0 , area = 0;
      for(int i=0;i<A.length;i++){
          int width = 1;
        for(int j=A[0].length-1;j>=0;j--){ 
           area = A[i][j]*width;  width++;
           maxArea = Math.max(maxArea,area);
        }
      }
      
      return maxArea;
   
    }
}