class Solution:
    def findMaxLength(self, nums):
        result = []
        current = 0
        for n in nums:
            if n == 0:
                current -= 1
            else:
                current += 1
            result.append(current)
        
        hm = dict()
        hm[0] = [-1, None]
        for ind, val in enumerate(result):
            if val in hm:
                hm[val][1] = ind
            else:
                hm[val] = [ind, None]
        
        maxLength = 0
        for key, value in hm.items():
            if value[1] is not None:
                new = value[1] - value[0]
                if new > maxLength:
                    maxLength = new
        return maxLength

s = Solution()
print("Expected: 2")
print("Got:", s.findMaxLength([1, 0]))