hdu 4989 Summary

#include<iostream>
#include<map>
#define ll long long
#define maxn 100+5
using namespace std;
ll a[maxn];
map<int,int>mapp;
int main()
{
int n;
while(cin>>n)
{
mapp.clear();
ll sum=0;
for(int i=0;i<n;i++)
{
cin>>a[i];
for(int j=0;j<i;j++)
{
if(mapp.find(a[i]+a[j])==mapp.end())
{
sum+=(a[i]+a[j]);
mapp[a[i]+a[j]]=1;
}
}
}
cout<<sum<<endl;
}
return 0;
}