완주하지 못한 선수 (해시)

programmers.co.kr/learn/courses/30/lessons/42576?language=python3

코딩테스트 연습 - 완주하지 못한 선수

# 방법 1
def solution(participant, completion):
    D = {x: 0 for x in set(participant)}

    # D: {'leo': 1, 'kiki': 1, 'eden': 1}
    for x in participant:
        D[x] += 1

    # D: {'leo': 1, 'kiki': 0, 'eden': 0}
    for x in completion:
        D[x] -= 1

    # ans: "leo"
    # ans = list(filter(lambda k: D[k] == 1, D))[0]
    ans = [k for k in D if D[k] == 1][0]
    return ans


# 방법 2
from collections import Counter


def solution(participant, completion):
    # D: {'leo': 1}
    D = Counter(participant) - Counter(completion)

    ans = list(D.keys())[0]
    return ans


res = solution(["leo", "kiki", "eden"], ["eden", "kiki"])
print(res)