Hello, Coderz, today we are going to solve **Variable Sized HackerRank Solution in C++**.

**Task**

Consider an n-element array, a, where each index i in the array contains a reference to an array of k_{i }integers (where the value of varies from array to array). See the Explanation section below for a diagram.

Given a, you must answer q queries. Each query is in the format i j, where i denotes an index in array a and j denotes an index in the array located at a[i]. For each query, find and print the value of element j in the array at location a[i] on a new line.

**Input Format**

The first line contains two space-separated integers denoting the respective values of n (the number of variable-length arrays) and q (the number of queries).

Each line i of the n subsequent lines contains a space-separated sequence in the format k a[i]_{0} a[i]_{1} … a[i]_{k-1} describing the k-element array located at a[i].

Each of the q subsequent lines contains two space-separated integers describing the respective values of i (an index in array a) and j (an index in the array referenced by a[i]) for a query.

**Constraints**

- 1 <= n <= 10
^{5} - 1 <= q <= 10
^{5} - 1 <= k <= 3 . 10
^{5} - n <= Σk <= 3 . 10
^{5} - 0 <= i < n
- 0 <= j < k
- All indices in this challenge are zero-based.
- All the given numbers are non negative and are not greater than 10
^{6}.

**Output Format**

For each pair of i and j values (i.e., for each query), print a single integer that denotes the element located at index j of the array referenced by a[i]. There should be a total of q lines of output.

**Sample Input**

```
2 2
3 1 5 4
5 1 2 8 9 3
0 1
1 3
```

**Sample Output**

```
5
9
```

**Explanation**

The diagram below depicts our assembled Sample Input:

We perform the following q=2 queries:

- Find the array located at index i = 0 , which corresponds to a[i] = [1,5,4]. We must print the value at index j=1 of this array which, as you can see, is 5.
- Find the array located at index i=1 , which corresponds to a[i] = [1,2,8,9,3]. We must print the value at index j=3 of this array which, as you can see, is 9.

**Solution – Variable Sized Arrays Hackerrank Solution in C++**

#include <iostream> #include <vector> using namespace std; int main() { // get length of array 'a' and number of queries int n, q; cin >> n >> q; // create vector of vectors vector<vector<int>> a(n); // fill each 2D vector i with k_i values for (int i = 0; i < n; i++) { // get the length k of the vector at a[i] int k; cin >> k; // fill the vector with k values a[i].resize(k); for (int j = 0; j < k; j++) { cin >> a[i][j]; } } // run queries on a for (int q_num = 0; q_num < q; q_num++) { // get i, j as the 'query' to get a value from a int i, j; cin >> i >> j; cout << a[i][j] << endl; } return 0; }

**Disclaimer:** The above problem (**Variable Sized Arrays**) is generated by **Hacker Rank** but the Solution is provided by** CodingBroz**.

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