1422. Maximum Score After Splitting a String - Explanation

class Solution:
    def maxScore(self, s: str) -> int:
        n, res = len(s), 0
        for i in range(1, n):
            left_zero = 0
            for j in range(i):
                if s[j] == '0':
                    left_zero += 1
            right_one = 0
            for j in range(i, n):
                if s[j] == '1':
                    right_one += 1
            res = max(res, left_zero + right_one)
        return res

class Solution:
    def maxScore(self, s: str) -> int:
        n = len(s)
        left_zero = [0] * n
        right_one = [0] * n

        if s[0] == '0':
            left_zero[0] = 1
        for i in range(1, n):
            left_zero[i] = left_zero[i - 1]
            if s[i] == '0':
                left_zero[i] += 1

        if s[n - 1] == '1':
            right_one[n - 1] = 1
        for i in range(n - 2, -1, -1):
            right_one[i] = right_one[i + 1]
            if s[i] == '1':
                right_one[i] += 1

        res = 0
        for i in range(1, n):
            res = max(res, left_zero[i - 1] + right_one[i])
        return res

class Solution:
    def maxScore(self, s: str) -> int:
        zero = 0
        one = s.count('1')
        res = 0

        for i in range(len(s) - 1):
            if s[i] == '0':
                zero += 1
            else:
                one -= 1
            res = max(res, zero + one)

        return res

class Solution:
    def maxScore(self, s: str) -> int:
        # res = Max of all (left_zeros + right_ones)
        # res = Max of all (left_zeros + (total_ones - left_ones))
        # res = total_ones (constant) + Max of all (left_zeros - left_ones)

        zeros = 0
        ones = 0

        if s[0] == '0':
            zeros += 1
        else:
            ones += 1

        res = float('-inf')
        for i in range(1, len(s)):
            res = max(res, zeros - ones)
            if s[i] == '0':
                zeros += 1
            else:
                ones += 1

        return res + ones