Program to check if an Array is Palindrome or not - GeeksforGeeks

22 Mar, 2021
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++
Java
Python3
C#
PHP
Javascript
// 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;}
// 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);    }}
# Python3 Program to check whether the# Array is palindromic or notdef 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
// C# Program to check whether the// Array is palindromic or notclass 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
<?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?>
<script> // Javascript Program to check whether the// Array is palindrome or not  function palindrome(arr, n){    // Initialise flag to zero.    let flag = 0;     // Loop till array size n/2.    for (let 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)        document.write("Not Palindrome");    else        document.write("Palindrome");} // Driver code.      let arr = [ 1, 2, 3, 2, 1 ];    let n = arr.length;     palindrome(arr, n); // This code is contributed by Mayank Tyagi </script>
Palindrome
 
Related Article: Program to check if an array is palindrome or not using Recursion 
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