Main.cpp

#include <iostream>
using namespace std;
int main(void){
    // Here your code !
    int n=4;
    int a[]={1,2,4,7};
    int k=15;
    unsigned int maxbmap=(1 << n);
    
    for(int bmap=0; bmap<maxbmap; bmap++){
        int subsetsum=0;
        for(int j=0; j<n; j++){
            if(0 != (bmap & (1 << j))){
                subsetsum += a[j];
            }
        }
        if(k == subsetsum){
            std::cout << "Yes" << std::endl;
            return 0;
        }
    }
    std::cout << "No" << std::endl;
    return 0;
}