LargestSubMatrix.java

// 1727. Largest Submatrix With Rearrangements

import java.util.*;
class Solution {
    public int largestSubmatrix(int[][] matrix) {
        int m = matrix.length;
        int n = matrix[0].length;

        for(int i = 1; i < m; i++){
            for(int j = 0; j < n; j++){
                if(matrix[i][j] != 0){
                    matrix[i][j] += matrix[i-1][j];
                }
            }
        }
        int maxArea = 0;
        for(int i = 0; i < m; i++){
            int[] row = new int [n];
            for(int j = 0; j < n; j++){
                row[j] = matrix[i][j];
            }
            Arrays.sort(row);

            for(int j = 0; j < n; j++){
                int height = row[j];
                int width = n - j;
                maxArea = Math.max(maxArea, height * width);
            }
        }
        return maxArea;
    }
}