包AC

#include<bits/stdc++.h>
using namespace std;

int cnt[100+5],n,a,r,t;
int main(){
	cin >> n;
	for(int i=0; i<n; i++){
		cin >> a;
		cnt[a]++;
	}
	for(int i=0; i<=100; i++){
		for(int j=0; j<cnt[i]; j++){
			t+=i;
			r+=t;
		}
	}
	cout << r;
	return 0;
} 

#include <iostream>
#include <algorithm>
using namespace std;
int maxx=0x3f3f3f;
const int N=1e3+10;
int a[N] ,sum,cnt,n;
int main()
{		
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		cin>>a[i];
	}
	sort(a+1,a+n+1);
	for(int i=1;i<=n;i++)
	{
		sum=sum+(a[i]+cnt);
		cnt+=a[i];
	}
	cout<<sum;
	return 0;
}

#include <iostream>
using namespace std;
int main()
{
	int s,t,n,a[1001]; 
	cin >> n;
	for(int i = 1;i <= n;i++)
		cin >> a[i];
	sort(a+1,a+1+n);
	s = t = a[1];
	for(int i = 2;i <= n;i++) {
		s += a[i]+t;
		t += a[i];
	}
	cout << s;
	return 0;
}

论前缀和的用处

#include <bits/stdc++.h>
using namespace std;
const int N=1e5+10;
const int INF=0x3f3f3f3f;
int a[N],s[N],ans;
int main()
{
	int n;
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		cin>>a[i];
	}
	sort(a+1,a+n+1);
	for(int i=1;i<=n;i++)
	{
		s[i]=a[i]+s[i-1];
		ans+=s[i];
	}
	cout<<ans;
}

#include <math.h>
#include <stack>
#include <stdio.h>
#include <iostream>
#include <vector>
#include <iomanip>
#include <string.h>
#include <algorithm>
using namespace std;
#define LL long long
#define ull unsigned long long
const int N = 1e3 + 10;
const int INF = 0x3f3f3f3f;
int n,a[N],cnt,sum;
int main(void){
	cin >> n;
	for (int i=1; i<=n; i++){
		cin >> a[i];
		
	}
	sort(a+1, a+n+1);
	
	for (int i=1; i<=n; i++){
		sum=sum+(a[i]+cnt);
		cnt = cnt +a[i];
	}
	cout << sum << endl;
	return 0;
} 
```

#include <queue>
#include <math.h>
#include <stack>
#include <stdio.h>
#include <iostream>
#include <vector>
#include <iomanip>
#include <string.h>
#include <algorithm>
using namespace std;
#define LL long long
#define ull unsigned long long
const int N = 1e3 + 10;
const int INF = 0x3f3f3f3f;
int a[N];
int main()
{
	int n;
	cin >> n;
	for(int i = 0 ; i < n ; i++)
		cin >> a[i];
	sort(a,a+n);
	int ans = 0;
	for(int i = 0 , j = n ; i < n , j > 0 ; i++ , j--)
		ans += a[i] * j;
	cout << ans << endl;
	return 0;
}