Concatenate given array twice
Last Updated :
17 Feb, 2022
Given an array arr[] of N elements, the task is to concatenate it twice, i.e. create an array of size 2*N by appending the copy of the given array to itself.
Example:
Input: arr[] = {1, 2, 1}
Output: 1 2 1 1 2 1
Explanation: The given array arr[] = {1, 2, 1}, can be appended to itself resulting in arr[] = {1, 2, 1, 1, 2, 1}.
Input: arr[] = {1, 3, 2, 1}
Output: 1 3 2 1 1 3 2 1
Approach: The given problem is an implementation-based problem. It can be solved by creating a array newArr[] of size 2*N. Iterate the given array arr[] using a variable i in the range [0, N) and append the assign newArr[i] = arr[i] and newArr[i + N] = arr[i].
Below is the implementation of the above approach:
C++
#include <bits/stdc++.h>
using namespace std;
void concatTwice( int * arr, int N)
{
int newArr[2 * N];
for ( int i = 0; i < N; i++) {
newArr[i] = arr[i];
newArr[i + N] = arr[i];
}
for ( int i = 0; i < 2 * N; i++) {
cout << newArr[i] << " " ;
}
}
int main()
{
int arr[] = { 1, 2, 3 };
int N = sizeof (arr) / sizeof (arr[0]);
concatTwice(arr, N);
return 0;
}
|
Java
import java.io.*;
import java.lang.*;
import java.util.*;
class GFG {
static void concatTwice( int arr[], int N)
{
int newArr[] = new int [ 2 * N];
for ( int i = 0 ; i < N; i++) {
newArr[i] = arr[i];
newArr[i + N] = arr[i];
}
for ( int i = 0 ; i < 2 * N; i++) {
System.out.print(newArr[i] + " " );
}
}
public static void main (String[] args) {
int arr[] = { 1 , 2 , 3 };
int N = arr.length;
concatTwice(arr, N);
}
}
|
Python3
def concatTwice(arr, N):
newArr = [ 0 ] * ( 2 * N)
for i in range (N):
newArr[i] = arr[i]
newArr[i + N] = arr[i]
for i in range ( 0 , 2 * N):
print (newArr[i], end = " " )
arr = [ 1 , 2 , 3 ]
N = len (arr)
concatTwice(arr, N)
|
C#
using System;
class GFG {
static void concatTwice( int []arr, int N)
{
int []newArr = new int [2 * N];
for ( int i = 0; i < N; i++) {
newArr[i] = arr[i];
newArr[i + N] = arr[i];
}
for ( int i = 0; i < 2 * N; i++) {
Console.Write(newArr[i] + " " );
}
}
public static void Main () {
int []arr = { 1, 2, 3 };
int N = arr.Length;
concatTwice(arr, N);
}
}
|
Javascript
<script>
const concatTwice = (arr, N) => {
let newArr = new Array(2 * N).fill(0);
for (let i = 0; i < N; i++) {
newArr[i] = arr[i];
newArr[i + N] = arr[i];
}
for (let i = 0; i < 2 * N; i++) {
document.write(`${newArr[i]} `);
}
}
let arr = [1, 2, 3];
let N = arr.length;
concatTwice(arr, N);
</script>
|
Time Complexity: O(N)
Auxiliary Space: O(N)
Like Article
Suggest improvement
Share your thoughts in the comments
Please Login to comment...