P2415 集合求和
#include<bits/stdc++.h>
using namespace std;int main(){long long sum = 0;int num = 0;int t;while(cin >> t){sum += t;num++;}cout << (long long)(sum*pow(2 , num -1)); return 0;
}
#include<bits/stdc++.h>
using namespace std;int main(){long long sum = 0;int num = 0;int t;while(cin >> t){sum += t;num++;}cout << (long long)(sum*pow(2 , num -1)); return 0;
}