Arrays – DS Hackerrank problem solution

                                         Arrays - DS Hackerrank
Arrays – DS Hackerrank

An array is a type of data structure that stores elements of the same type in a contiguous block of memory. In an array, A, of size N, each memory location has some unique index, i (where 0<=i<=N), that can be referenced as A[i] (you may also see it written as Ai).

Given an array, A, of N integers, print each element in reverse order as a single line of space-separated integers.

Input Format

The first line contains an integer, N (the number of integers in A).
The second line contains N space-separated integers describing A.

Constraints

1<=N<=103
1<=Ai<=104 where Aiis ith integer in A
Output Format

Print all N integers in A in reverse order as a single line of space-separated integers.

Sample Input

4
1 4 3 2

Sample Output

2 3 4 1

Solution

The 2 solutions provided below both follow this basic logic:
Write each element of input into an array.
Iterate through the array in reverse, printing each element as you go.

#include <iostream>
using namespace std;
int main()
{
  int n,i;
  cin>>n;
  int a[n];
  for(i=0;i<n;i++)
  {
   cin>>a[i];
  } 
  for(i=n-1;i>=0;i--)
  {
   cout<<a[i]<<" ";
  }
 return 0;
}

import java.util.*;

public class Solution {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int[] array = new int[scan.nextInt()];
        for(int i = 0; i < array.length; i++){
            array[i] = scan.nextInt();
        }
        scan.close();
        
        for(int i = array.length - 1; i >= 0; i--){
            System.out.print(array[i] + " ");
        }
    }
}

 

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>

int main() {

    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int i,n,arr[1000];
    scanf("%d",&n);
    
    for(i=0;i<n;i++)
        scanf("%d",&arr[i]);
   
    for(i=n-1;i>=0;i--)
    printf("%d ",arr[i]);
    
    return 0;
}
import java.util.*;

public class Solution {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int n = Integer.parseInt(scan.nextLine());
        String[] array = scan.nextLine().split(" ");
        scan.close();
        
        while(--n >= 0){
            System.out.print(array[n] + " ");
        }
    }
}
# Enter your code here. Read input from STDIN. Print output to STDOUT
input()
arr = raw_input().split()

print " ".join(reversed(arr))
# Enter your code here. Read input from STDIN. Print output to STDOUT

N = input()
A = [int(x) for x in raw_input().split()]


print ' '.join([str(x) for x in reversed(A)])

A web developer(Front end and Back end), and DBA at csdamu.com. Currently working as Salesforce Developer @ Tech Matrix IT Consulting Private Limited. Check me @about.me/s.saifi

5 comments: On Arrays – DS Hackerrank problem solution

  • Thanks, buddy for the answer.

  • your python code is not working ???
    check mine:

    Solution:
    array = []
    intsize = int(input())
    for i in range(intsize):
    array.append(int(input()))
    for j in reversed(range(len(array))):
    print(array[j], end=” “)

  • Hello Steve, thanx. For your interest. You have asked about the two for loops and going in details if you see..in the first loop we are taking the input in the array while in the second we are printing it from last and the last limit is stored at n-1 index.
    arr[I] is the element of array at ith index.
    Hope it will help you.For any further assistance please revert me back.
    Thank you

  • Hi! Thanks for the answer but can you please explain it with comments to describe what each line of code does. Especially…
    for(i=0;i>a[i];
    }
    for(i=n-1;i>=0;i–)
    {
    cout<<a[i]<<" ";

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