시소 짝꿍

from collections import Counter def solution(weights): answer = 0 # 같은 weight가 있는 경우는 따로 처리해줍니다. counter = Counter(weights) for w, cnt in counter.items(): answer += cnt * (cnt - 1) // 2 wset = set(weights) for w in weights: # 4/3배 if w % 3 == 0: target_weight = w * 4 // 3 answer += counter[target_weight] # 3/2배 if w % 2 == 0: target_weight = w * 3 // 2 answer += counter[target_weight] # 2배 target_weight = w * 2 answer += counter[target_weight] return answer