https://www.hackerrank.com/contests/code-cpp-3/challenges/variable-sized-arrays

hackerank1.cpp

#include <iostream>
using namespace std;

int main() {
    int **seq;

    int N, Q;
    cin >> N;
    cin >> Q;
    //cout << N << " " << Q;
    seq = new int*[N];

    for(int i = 0; i<N; i++){
        int x, y;
        cin >> x;
        //cout << " " << x;
        int *seqs = new int[x];
        for(int h=0; h<x; h++){
            cin >> y;
            seqs[h] = y;
        }
        seq[i] = seqs;
    }

    for(int i=0; i<Q; i++){
        int a, b;
        cin >> a;
        cin >> b;

        cout << seq[a][b] << "\n";
    }

	return 0;
}