Variable Sized Arrays in C++ – Solution in Hacker Rank - hackerranksolutions8

 

Problem

Consider an n-element array, a, where each index i in the array contains a reference to an array of ki integers (where the value of ki 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.
Click here to know more about how to create variable sized arrays in C++.

---

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<=k<=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 denoting 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:

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

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#define MAX 1000
using namespace std;


int main() 
{
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
    int arr1[MAX][MAX],size[MAX];
    int n,q,s,pos1,pos2;
    cout<<"Enter a Number of Array";
    cin>>n>>q; 
    for(int i=0;i<n;i++)
    {
       cout<<"Enter a size of array";
       cin>>s;
       for(int j=0;j<s;j++)
       {
            cin>>arr1[i][j];
       } 
        
    }
    for(int i=0;i<q;i++)
    {
        cout<<"Enter a position";
        cin>>pos1>>pos2;
        cout<<arr1[pos1][pos2]<<"\n";
    }
    return 0;
}