Managing Difficulties

#include<bits/stdc++.h>
using namespace std;
#define FOR(i,n,m) for(int i=n;i<=m;i++)
//#define gc getchar()
inline int read();static char buf[1000000],*pa=buf,*pb=buf;
#define gc pa==pb&&(pb=(pa=buf)+fread(buf,1,1000000,stdin),pa==pb)?EOF:*pa++
const int N=2010;
int n,ct,ak,a[N];
map<int,int> m;
int main()
{
    int t=read();FOR(i,1,t){
    m.clear();
    n=read();ct=0;
    FOR(i,0,n-1) a[i]=read();
    m[a[0]]=1;
    FOR(i,1,n-2)
    {
        FOR(j,i+1,n-1)
        {
            ak=2*a[i]-a[j];
            if(ak>=0 && m.count(ak)) ct+=m[ak];
        }
        ++m[a[i]];
    }
    printf("%d
",ct);
    }return 0;
}


inline int read()
{
    register int x(0);register char c(gc);bool bbb=1;
    if(c=='-') {c=gc;}
    while(c<'0'||c>'9')c=gc;
    while(c>='0'&&c<='9')x=(x<<1)+(x<<3)+(c^48),c=gc;
    if(bbb)return x;
    else return -x;
}