题解 | #24点游戏算法#

#include<vector>
using namespace std;
bool hasSolution(vector<double> a,double result){
    if(a.empty()){
        return result==24;
    }
    for(int i=0;i<a.size();i++){
        vector<double> rest=a;
        rest.erase(i+rest.begin());
        if(hasSolution(rest,result+a[i])||hasSolution(rest,result-a[i])
           ||hasSolution(rest,result*a[i])||hasSolution(rest,result/a[i])){
            return true;
        }
    }
    return false;
}
int main(){
    double a,b,c,d;
    while(cin>>a>>b>>c>>d){
        vector<double>vec;
        vec.push_back(a);
        vec.push_back(b);
        vec.push_back(c);
        vec.push_back(d);
        bool result=hasSolution(vec,0);
        if(result){
            cout<<"true"<<endl;
        }
        else{
            cout<<"false"<<endl;
        }
    }
}