ref - map (inserting+traversing:easy way) - Random Sort Gy

#include <bits/stdc++.h>
using namespace std;
#define d(x)                cout << #x << " = " << (x) << endl;
#define fr                  freopen("in.txt", "r", stdin);
#define fw                  freopen("out.txt", "w", stdout);
#define mem(x)              memset((x), 0, sizeof((x)));
#define pb                  push_back
#define LL                  long long
#define fastIO              ios_base::sync_with_stdio(false)
#define sf                  scanf
#define pf                  printf
#define sc1(x)              scanf("%d", &x)
#define sc2(x, y)           scanf("%d %d", &x, &y)
#define sc3(x, y, z)        scanf("%d %d %d", &x, &y, &z)
#define FOR(i, x, y)        for(int i=int(x); i<int(y); i++)
#define ROF(i, x, y)        for(int i=int(x-1); i>=int(y); i--)
#define all(c)              c.begin(), c.end()
#define unq(v)              sort(all(v)), (v).erase(unique(all(v)),v.end())
#define siz 1000000
#define MAX 100000
vector<LL> edge[MAX];
vector<LL> cost;
vector<LL> visited(MAX);
vector<LL> dist;
LL ans = 0;
LL taka = INT_MAX;

#define mod 7901
map<int, int> mymap;
int facto(int n){
    int fact = 1;
    for(int i = 1; i <= n; i++){
        fact = (fact * i)%mod;
    }
    return fact%mod;
}

main(){
    fastIO;
    fr; fw;
    int tc;
    cin >> tc;
    for(int tr = 1; tr <= tc; tr++){
        //clearing map in every iteration
        mymap.clear();
        int n;
        cin >> n;
        int ara[n];
        //Global <int, int> maps has 0 decraled as default in value side of key-value pair
        FOR(i, 0, n) {
            cin >> ara[i];
            mymap[ara[i]]++;
        }

       int ans = 1;
       //traversing through map using auto loop
       for(auto p: mymap){
           ans = (ans*facto(p.second))%mod;
       }
        cout << ans%mod << endl;
    }
}