Program to check if an Array is Palindrome or not

Given an array, the task is to determine whether an array is a palindrome or not.

Examples:

Input: arr[] = {3, 6, 0, 6, 3}
Output: Palindrome

Input: arr[] = {1, 2, 3, 4, 5}
Output: Not Palindrome

Approach:

  • Initialise flag to unset int flag = 0.
  • Loop the array till size n/2
  • In a loop check if arr[i]! = arr[n-i-1] then set the flag = 1 and break
  • After the loop has ended, If flag is set the print “Not Palindrome” else print “Palindrome”

Below is the implementation of above Approach:

C++

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// C++ Program to check whether the
// Array is palindrome or not
  
#include <iostream>
using namespace std;
  
void palindrome(int arr[], int n)
{
    // Initialise flag to zero.
    int flag = 0;
  
    // Loop till array size n/2.
    for (int i = 0; i <= n / 2 && n != 0; i++) {
  
        // Check if first and last element are different
        // Then set flag to 1.
        if (arr[i] != arr[n - i - 1]) {
            flag = 1;
            break;
        }
    }
  
    // If flag is set then print Not Palindrome
    // else print Palindrome.
    if (flag == 1)
        cout << "Not Palindrome";
    else
        cout << "Palindrome";
}
  
// Driver code.
int main()
{
    int arr[] = { 1, 2, 3, 2, 1 };
    int n = sizeof(arr) / sizeof(arr[0]);
  
    palindrome(arr, n);
    return 0;
}

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Java

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// Java Program to check whether the
// Array is palindromic or not
  
class GfG {
  
    static void palindrome(int arr[], int n)
    {
        // Initialise flag to zero.
        int flag = 0;
  
        // Loop till array size n/2.
        for (int i = 0; i <= n / 2 && n != 0; i++) {
  
            // Check if first and last element are different
            // Then set flag to 1.
            if (arr[i] != arr[n - i - 1]) {
                flag = 1;
                break;
            }
        }
  
        // If flag is set then print Not Palindrome
        // else print Palindrome.
        if (flag == 1)
            System.out.println("Not Palindrome");
        else
            System.out.println("Palindrome");
    }
  
    // Driver code.
    public static void main(String[] args)
    {
        int arr[] = { 1, 2, 3, 2, 1 };
        int n = arr.length;
  
        palindrome(arr, n);
    }
}

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Python3

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# Python3 Program to check whether the
# Array is palindromic or not
def palindrome(arr, n):
  
    # Initialise flag to zero.
    flag = 0;
  
    # Loop till array size n/2.
    i = 0;
    while (i <= n // 2 and n != 0):
  
        # Check if first and last element 
        # are different. Then set flag to 1.
        if (arr[i] != arr[n - i - 1]):
            flag = 1;
            break;
        i += 1;
  
    # If flag is set then print Not Palindrome
    # else print Palindrome.
    if (flag == 1):
        print("Not Palindrome");
    else:
        print("Palindrome");
  
# Driver code.
arr = [ 1, 2, 3, 2, 1 ];
n = len(arr);
  
palindrome(arr, n);
  
# This code is contributed 
# by chandan_jnu

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C#

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// C# Program to check whether the
// Array is palindromic or not
class GfG 
{
  
    static void palindrome(int []arr, int n)
    {
        // Initialise flag to zero.
        int flag = 0;
  
        // Loop till array size n/2.
        for (int i = 0; i <= n / 2 && n != 0; i++) 
        {
  
            // Check if first and last element are different
            // Then set flag to 1.
            if (arr[i] != arr[n - i - 1])
            {
                flag = 1;
                break;
            }
        }
  
        // If flag is set then print Not Palindrome
        // else print Palindrome.
        if (flag == 1)
            System.Console.WriteLine("Not Palindrome");
        else
            System.Console.WriteLine("Palindrome");
    }
  
    // Driver code.
    static void Main()
    {
        int []arr = { 1, 2, 3, 2, 1 };
        int n = arr.Length;
  
        palindrome(arr, n);
    }
}
  
// This code is contributed by chadan_jnu

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PHP

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<?php
// PHP Program to check whether the
// Array is palindrome or not
  
function palindrome($arr, $n)
{
    // Initialise flag to zero.
    $flag = 0;
  
    // Loop till array size n/2.
    for ($i = 0; $i <= $n / 2 && 
                 $n != 0; $i++)
    {
  
        // Check if first and last element are 
        // different then set flag to 1.
        if ($arr[$i] != $arr[$n - $i - 1]) 
        {
            $flag = 1;
            break;
        }
    }
  
    // If flag is set then print Not Palindrome
    // else print Palindrome.
    if ($flag == 1)
        echo "Not Palindrome";
    else
        echo "Palindrome";
}
  
// Driver code.
$arr = array( 1, 2, 3, 2, 1 );
$n = count($arr);
  
palindrome($arr, $n);
  
// This code is contributed by chandan_jnu
?>

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Output:

Palindrome

Related Article: Program to check if an array is palindrome or not using Recursion

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