flip.py

class Solution:
    def flip(self, A):
        max_diff = 0
        diff = 0
        start = 0
        ans = None

        for i, a in enumerate(A):
            diff += (1 if a is '0' else -1)

            if diff < 0:
                diff = 0
                start = i + 1
                continue

            if diff > max_diff:
                max_diff = diff
                ans = [start, i]

        if ans is None:
            return []
        return list(map(lambda x: x + 1, ans))


"""
Testing Code
"""

a = "010"
s = Solution()
print(s.flip(a))