[Codility/Lesson3]PermissionElem

어디서 본 듯한 .... 근데 in 써서 풀면 안되는(느림)

import collections

def solution(A):

    count_hash = collections.defaultdict(int)

    for count in A:
        count_hash[count] += 1
    
    for num in range(1, len(A) + 2):
        if count_hash[num] == 0:
            return num

결과는 여기에