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 the flag is set to 1 then print “Not Palindrome” else print “Palindrome”
Below is the implementation of above Approach:
C++
// 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
// Java Program to check whether the// Array is palindrome 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.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
# 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#
// 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// PHP Program to check whether the// Array is palindrome or notfunction 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?> |
Javascript
<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> |
Output:
Palindrome
Time complexity: O(n) where n is size of given array
Auxiliary space: O(1)
Related Article: Program to check if an array is palindrome or not using Recursion
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