Score After Flipping Matrix — Python

# Time:  O(r * c)
# Space: O(1)


class Solution(object):
    def matrixScore(self, A):
        """
        :type A: List[List[int]]
        :rtype: int
        """
        R, C = len(A), len(A[0])
        result = 0
        for c in xrange(C):
            col = 0
            for r in xrange(R):
                col += A[r][c] ^ A[r][0]
            result += max(col, R-col) * 2**(C-1-c)
        return result