【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