자료구조 | 3-2 완주하지못한선수

from collections import Counter

def solution(participant, completion):
      participant.sort()
      completion.sort()
      answer = Counter(participant) - Counter(completion)
      
      return list(answer.keys())[0]

solution(["leo", "kiki", "eden"], ["eden", "kiki"])
print("==========================================")
solution(["marina", "josipa", "nikola", "vinko", "filipa"], ["josipa", "filipa", "marina", "nikola"])
print("==========================================")
solution(["mislav", "stanko", "mislav", "ana"], ["stanko", "ana", "mislav"])
print("==========================================")