[最大最长]最长子数组（含有相同数量的 0 和 1 的）（前缀和）

class Solution:
    def findMaxLength(self, nums: List[int]) -> int:

        map= {0:-1}
        n = len(nums)
        count = 0
        max_len = 0
        for i in range(n):
            if nums[i] == 0:
                count += -1
            else:
                count += 1
            
            if count in map:
                max_len = max(max_len,i-map[count])
            else:
                map[count] = i 
        
        return max_len