Codeforces Round #251 (Div. 2) B. Devu, the Dumb Guy

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main(){
long long n,x;
cin >> n >> x;
vector<long long> c(n);
for(int i = 0 ; i < n; ++ i) cin >> c[i];
sort(c.begin(),c.end());
long long res = 0;
for(int i = 0 ; i <  n; ++ i){
res +=c[i]*(x> 1 ? x--: 1);
}
cout<<res<<endl;
}