Palindrome.java

/* Check Palindrome

Given a string, determine if it is a palindrome, considering only alphanumeric characters.
Palindrome
A palindrome is a word, number, phrase, or other sequences of characters which read the same backwards and forwards.
Example:
If the input string happens to be, "malayalam" then as we see that this word can be read the same as forward and backwards, it is said to be a valid palindrome.

The expected output for this example will print, 'true'.
From that being said, you are required to return a boolean value from the function that has been asked to implement.
Input Format:
The first and only line of input contains a string without any leading and trailing spaces. All the characters in the string would be in lower case.
Output Format:
The only line of output prints either 'true' or 'false'.
Note:
You are not required to print anything. It has already been taken care of.
Constraints:
0 <= N <= 10^6
Where N is the length of the input string.

Time Limit: 1 second
Sample Input 1 :
abcdcba
Sample Output 1 :
true  
*/
import java.lang.System;
import java.util.*;

public class Palindrome {
    public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            String s = sc.nextLine();

            int i = 0, j = s.length() - 1;
            boolean isPalindrome = true;
            while (i < j) {
                if (s.charAt(i) != s.charAt(j)) {
                    isPalindrome = false;
                    break;
                }
                i++;
                j--;
            }
            System.out.println(isPalindrome);
        }
    }
}