Variable Sized Arrays Discussions | C++ | HackerRank Variable Length Arrays in C and C++ - GeeksforGeeks

Variable Sized Arrays

Variable Sized Arrays Discussions | C++ | HackerRank

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

Given , you must answer  queries. Each query is in the format i j, where  denotes an index in array  and  denotes an index in the array located at . For each query, find and print the value of element  in the array at location  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  (the number of variable-length arrays) and  (the number of queries).
Each line  of the  subsequent lines contains a space-separated sequence in the format k a[i]0 a[i]1 … a[i]k-1 describing the -element array located at .
Each of the  subsequent lines contains two space-separated integers describing the respective values of  (an index in array ) and  (an index in the array referenced by ) for a query.

Constraints

• All indices in this challenge are zero-based.
• All the given numbers are non negative and are not greater than 

Output Format

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

1. Find the array located at index , which corresponds to . We must print the value at index  of this array which, as you can see, is .
2. Find the array located at index , which corresponds to . We must print the value at index  of this array which, as you can see, is .

#include <cmath>

#include <cstdio>

#include <vector>

#include <iostream>

#include <algorithm>

using namespace std;

int main()

{

    int n,q,i=0,data,num,a,b;

    //cout<<"enter number of array you want and no of query to be asked"<<endl;

    cin>>n>>q;

    int *arr1[n];

    while(n--)

    {     //cout<<"how long you want to make inner array enter number";

        cin>>num;

        arr1[i]= new int[num];

        for(int j=0;j<num;j++)

        {

           // cout<<"enter no in array";

            cin>>data;

            arr1[i][j] =data;

        }

        

        

        i++;

       

        

    }

    

    while(q--)

    {

        //cout<<"enter  index no for rwo and column";

        cin>>a>>b;

        cout<<arr1[a][b]<<endl;

        

    }

    

    

    return 0;

} 

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