BZOJ 2697 Watery Problem

https://www.lydsy.com/JudgeOnline/problem.php?id=2697

A Watery Problem

Just using the Greedy Algorithm to solve it

code of AC:

#include<bits/stdc++.h>
using namespace std;
int A[2000];
int main(){
    int n,k;
    cin>>n>>k;
    for(int i=1;i<=k;++i){
        cin>>A[i];
    }
    sort(A+1,A+1+k);
    int ans=0;
    for(int i=k;i>=1&&n>=2;--i){
        ans+=(n-1)*A[i];
        n-=2;
    }
    cout<<ans<<endl;
}