시소 짝꿍

문제

def solution(weights):
    # 균형 조합
    ss = dict()
    answer = 0
    # dict 입력 받기
    for weight in weights:
        weight = int(weight)
        if weight not in ss.keys():
            ss[weight] = 1
        else:
            ss[weight] += 1
    
    # 같은 수일 때
    for key in ss.keys():
        if ss[key] >= 2:
            answer += ss[key] * (ss[key] -1) // 2
    
    # 2:3, 2:4, 3:4
    for key in ss.keys():
        if key * 2/3 in ss.keys():
            answer += ss[key * 2/3] * ss[key]
        if key * 2/4 in ss.keys():
            answer += ss[key * 2/4] * ss[key]
        if key * 3/4 in ss.keys():
            answer += ss[key * 3/4] * ss[key]
    
    return answer