题解 | 24点游戏算法

def fn(nums):
    if len(nums) == 1 and abs(nums[0] - 24) < 10**(-6): #nums中只有一个元素，且值为24，终止递归
        return True
    for i in range(len(nums)):
        for j in range(i+1,len(nums)): #在nums中任意取两个元素a，b，用两个for循环遍历到所有可能
            a = nums[i]
            b = nums[j]
			
            new_list = [v for k,v in enumerate(nums) if k not in {i,j}] #去除a，b后的列表
            
            operations = [a+b,a-b,b-a,a*b] #对a，b两个数做任何运算操作
            if a != 0:
                operations.append(b/a)
            if b != 0:
                operations.append(a/b)
            for result in operations:
                if fn(new_list + [result]):  #递归，对a，b做四则运算操作的值，加到去除a，b后的列表中
                    return True
    return False

while True:
    try:
        nums = list(map(int,input().split()))
        if fn(nums):
            print("true")
        else:
            print("false")

    except:
        break