Variable Sized Arrays

variable_size_arrays.cpp

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    int n{}, q{};
    cin >> n >> q;  
    vector <vector<int>> a;
    
    for(int i = 0; i < n; ++i) {
        a.push_back(vector<int>());
        int k{};
        cin >> k;
        for(int j = 0; j < k; ++j) {
            int m;
            cin >> m;
            a[i].push_back(m);
        }
    }
    
    
    for(int i = 0; i < q; ++i) {
        int p{}, q{};
        cin >> p >> q;
        cout << a.at(p).at(q) << endl;
    }
    
    return 0;
}