[220204] Contiguous Array

class Solution:
    def findMaxLength(self, nums):

        # 记录目前为止的 pattern
        temp = 0
        res = 0
        mp = {0:-1}

        for i, num in enumerate(nums):
            if num == 0:
                temp -= 1
            else:
                temp += 1

            # 记录新 pattern 和对应的 index 值
            if temp not in mp:
                mp[temp] = i
            # 同 value 表示中间的 0 和 1 个数相等，更新 length
            else:
                res = max(res, i - mp[temp])

        return res