
You are given a binary matrix matrix of size m x n , and you are allowed to rearrange the columns of the matrix in any order.
Return the area of the largest submatrix within matrix where every element of the submatrix is 1 after reordering the columns optimally.
m == matrix.lengthn == matrix[i].length1 <= m * n <= 10 ^5matrix[i][j] is either 0 or 1 .