[프로그래머스] 순위 (python)

https://programmers.co.kr/learn/courses/30/lessons/49191?language=python3

코딩테스트 연습 - 순위

 

set과 defaultdict를 이용한 풀이

---

from collections import defaultdict
def solution(n, results):
    answer = 0
    win, lose = defaultdict(set), defaultdict(set)
    for result in results:
            lose[result[1]].add(result[0])
            win[result[0]].add(result[1])

    for i in range(1, n + 1):
        for winner in lose[i]: win[winner].update(win[i])
        for loser in win[i]: lose[loser].update(lose[i])

    for i in range(1, n+1):
        if len(win[i]) + len(lose[i]) == n - 1: answer += 1
    return answer

플로이드 워셜을 이용한 풀이

---

def solution(n, results):
    total = [['?' for i in range(n)] for j in range(n)]

    for i in range(n):
        total[i][i] = 'SELF'

    for result in results:
        total[result[0]-1][result[1]-1] = 'WIN'
        total[result[1]-1][result[0]-1] = 'LOSE'

    for k in range(n):
        for i in range(n):
            for j in range(n):
                if total[i][k] == 'WIN' and total[k][j] == 'WIN':
                    total[i][j] = 'WIN'
                elif total[i][k] == 'LOSE' and total[k][j] == 'LOSE':
                    total[i][j] = 'LOSE'

    answer = 0

    for i in total:
        if '?' not in i:
            answer += 1

    return answer

윗처럼 풀었지만 밑에 풀이가 더 직관적으로 이해하기 쉬웠다.