题解 | dfs递归#24点游戏算法#

import copy
def dps(num):
    if len(num)==1:
        return abs(abs(num[0]) - 24) < 0.00001 
    for i in range(len(num)):
        for j in range(i+1, len(num)):
            n1,n2= num[i], num[j]
            rst = num[:i] + num[i+1:j] + num[j+1:]
            if dps([n1+n2]+rst):return True
            if dps([n1-n2]+rst):return True
            if dps([n1*n2]+rst):return True
            if n1!=0:
                if dps([n2/n1]+rst):
                    return True
            if n2!=0:
                if dps([n1/n2]+rst):
                    return True
    return False


while True:
    try:
        x = list(map(int,input().split()))
        print("true" if dps(x) else "false")
    except:
        break