题解 | #24点运算#主要还是怎么计算24点

import itertools

def fun(a, b, c, d):

card_dict = {
    '2': 2,
    '3': 3,
    '4': 4,
    '5': 5,
    '6': 6,
    '7': 7,
    '8': 8,
    '9': 9,
    '10': 10,
    'J': 11,
    'Q': 12,
    'K': 13,
    'A': 1
}
rules = ['+', '-', '*', '/']
# 把牌面转为整数
x, y, z, m = card_dict[a], card_dict[b], card_dict[c], card_dict[d]
# 一组数字计算中有三个加减乘除符号，计算所有可能性
for i in rules:
    for j in rules:
        for k in rules:
            # 因为是从左往右计算，把前面的括起来
            result = eval('((' + 'x' + i + 'y' + ')' + j + 'z' + ')' + k + 'm')
            if result == 24:
                return a + i + b + j + c + k + d
else:
    return False
            
            

while True:

try:
    card_list = input().split()
    if 'joker' in card_list or 'JOKER' in card_list:
        print('ERROR')
    else:
        # 所有的牌面顺序
        all_list = itertools.permutations(card_list)
        for each in all_list:
            a, b, c, d = each
            result = fun(a, b, c, d)
            if result:
                print(result)
        else:
            print('NONE')
    
except:
    break