题解 | #24点游戏算法#

#include<iostream>
#include<vector>
using namespace std;
bool check(vector<double> n, double a)
{
    if(n.empty())return a == 24;
    for(int i = 0; i < n.size(); i++)
    {
        vector<double> r(n);//r=n
        r.erase(r.begin() + i);
        if(check(r,a+n[i])||check(r,a-n[i])||check(r,a*n[i])||check(r,a/n[i]))
            return true;
    }
    return false;
}
int main()
{
    vector<double> nums(4); 
    while(cin >> nums[0] >> nums[1] >> nums[2] >> nums[3])
        if(check(nums, 0))cout << "true" << endl;
        else cout << "false" << endl;
}