given a matrix of N rows and M columns, each element of matrix is equal to 0 or 1 . we can swap any two rows of matrix any number of times. we are required to find the maximum area of a submatrix consisting of 1's only by swapping rows. constraints (1<=n,m<=5000) problem link: https://www.hackerearth.com/challenge/college/execute-final-round/algorithm/47da7e50ba054fdcb66c292b7f681fb5/ please help and thanks in advance.