学步园

贪心

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
typedef __int64 ll;
int const MAXN = 300010;
ll a[MAXN];
int main(){
    int n;
    scanf("%d",&n);
    ll s = 0;
    for(int i = 1;i <= n;i++){
        scanf("%I64d",&a[i]);
        s += a[i];
        //a[i] += a[i - 1];
    }
    sort(a+1,a+n+1);
    if(n == 1)cout<<s<<endl;
    else{
        ll ss = s;
        int cnt = 0;
        int i = 1;
        while(i <= n){
           cnt++;
           if(cnt & 1){
            ss -= a[i];
            if(ss == 0)break;
            s += a[i++];
           }
           else s += ss;
           //cout<<ss<<endl;
        }
        cout<<s<<endl;
    }
    return 0;
}