Level 1 완주하지 못한 선수 Python3

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

코딩테스트 연습 - 완주하지 못한 선수

 

최종 풀이

• GitHub https://github.com/hwayeon351/Programmers-Algorithms/blob/main/level1_완주하지못한선수.py

hwayeon351/Programmers-Algorithms

from collections import Counter
def solution(participant, completion):
    return list(Counter(participant)-Counter(completion))[0]

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풀이 과정

풀이 시간 13분

1. Counter 활용

from collections import Counter
def solution(participant, completion):
    return list(Counter(participant)-Counter(completion))[0]
#시간복잡도 = O(n) 공간복잡도 = O(n)

 

2. Hash 활용

def solution(participant, completion):
    players = dict()
    sum_key = 0
    for p in participant:
        key = hash(p)
        players[key] = p
        sum_key += key
    for c in completion:
        sum_key -= hash(c)
    return players[sum_key]

 

3. sort 활용

def solution(participant, completion):
    last = list(set(participant)-set(completion))
    if len(last) == 1: return last[0]
    participant.sort()
    completion.sort()
    for i in range(len(completion)):
        if participant[i] != completion[i]:
            return participant[i]
    return participant[-1]
#시간복잡도 = O(nlogn) 공간복잡도 = O(n)