[Hackerearth] Bob and Indices

Problem Link    : Bob and Indices 
Category        : Adhoc
Contest         : December Circuits'23  

#include "bits/stdc++.h"
using namespace std;
#define int     long long int
#define endl    '\n'
 
void input(vector<int> &nums) {
    for (int &num : nums) {
        cin >> num;
    }
}
 
signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);
    cout.precision(12);
 
    bool FILEIO = 1;
    if (FILEIO and fopen("in.txt", "r")) {
        freopen("B3.txt", "r", stdin);
    }
 
    int tc;
    cin >> tc;
    for (int tcase = 1; tcase <= tc; tcase++) {
        int n;
        cin >> n;
        vector<int> A(n), B(n), C(n);
        input(A);
        input(B);
        input(C);
        map<int, int> cache;
        for (int i = 0; i < n; i++) {
            cache[ B[ C[i] ] ]++;
        }
        int ans = 0;
        for (int x : A) {
            ans += cache[x];
        }
        cout << ans << endl;
    } 

}