#812 · #861 · Score After Flipping Matrix(翻转矩阵后的得分)

You are given an m x n binary matrix grid. A move picks any row or column and flips every value in it. The score of the matrix is the sum, over rows, of the row interpreted as a binary number. Maximise the score. Constraints: 1 <= m, n <= 20, grid[i][j] is 0 or 1.