Codeforces Close Tuples Easy

#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define pb push_back
#define p_b pop_back
#define si stack<int>
#define sll stack<ll>
#define sc stack<char>
#define vi vector<int>
#define vll vector<ll>
#define mii map<int, int>
#define msi map<string, int>
#define mci map<char, int>
#define qc queue<char>
#define qi queue<int>
#define qll queue<ll>
using namespace std;

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int t;
    cin >> t;
    while(t--){
        int n;
        cin >> n;
        vi v;
        for(int i = 0; i < n; i++){
            int x;
            cin >> x;
            v.pb(x);
        }

        sort(v.begin(), v.end());

        int count = 0;
        int i = 0;
        while(i < n-2){
            int tmp = i;
            int c = 0;
            int j = i+1;
            while(v[j]-v[i] <= 2 && j < n){
                if(v[j] == v[i]){
                    tmp = j;
                }
                j++;
                c++;
            }
            if(c >= 2){
                count += (c+1)*(c)*(c-1)/6;
            }
            i = tmp+1;
        }
        cout << count << "\n";
    }
    return 0;
}