【leetcode】861. Score After Flipping Matrix

题目如下：

解题思路：本题需要知道一个数字规律，即pow(2,n) > sum(pow(2,0)+pow(2,1)+...+pow(2,n-1))。所以，为了获得最大值，要保证所有行的最高位是1，即需要优先进行行变换，把最高位变成1。接下来就是列变换，把0多于1的列做变换变成1多于0的列即可。

代码如下：

class Solution(object):
    def matrixScore(self, A):
        """
        :type A: List[List[int]]
        :rtype: int
        """
        if len(A) == 0 or len(A[0]) == 0:
            return 0
        #set the highest bit to 1.Since pow(2,N) > sum(pow(2,0) + pow(2,1) + ...+pow(2,n-1)
        for i in range(len(A)):
            if A[i][0] == 1:
                continue
            else:
                for j in range(len(A[i])):
                    if A[i][j] == 0:
                        A[i][j] = 1
                    else:
                        A[i][j] = 0
        row = len(A)
        column = len(A[0])
        for i in range(column):
            count1 = 0
            count0 = 0
            for j in range(row):
                if A[j][i] == 0:
                    count0 += 1
                else:
                    count1 += 1
            if count0 > count1:
                #convert
                for j in range(row):
                    if A[j][i] == 0:
                        A[j][i] = 1
                    else:
                        A[j][i] = 0
        res = 0
        for i in A:
            v = ''.join([str(j) for j in i])
            res += int(v,2)
        return res