// Runtime: 0 ms, faster than 100.00% of Java online submissions for Score After Flipping Matrix.
class Solution {
    int[][] a;
    int m;
    int n;
    public int matrixScore(int[][] A) {
        a = A;
        m = a.length;
        n = a[0].length;

        for (int r = 0; r < m; r++)
            if (a[r][0] == 0) flipRow(r);

        for (int c = 0; c < n; c++) {
            int ones = 0;
            for (int r = 0; r < m; r++)
                if (a[r][c] == 1) ones++;

            if (ones <= m/2) flipColumn(c);
        }

        return score();
    }

    private int score() {
        int sum = 0;

        for (int r = 0; r < m; r++) {
            int num = 0;
            int p = 1;
            for (int c = n-1; c >= 0; c--){
                if (a[r][c] == 1) num += p;
                p <<= 1;
            }
            sum += num;
        }

        return sum;
    }

    private void flipColumn(int c) {
        for (int r = 0; r < m; r++) a[r][c] = 1 - a[r][c];
    }

    private void flipRow(int r) {
        for (int c = 0; c < n; c++) a[r][c] = 1 - a[r][c];
    }
}