Palindrome Check (Recursive)

/*
 * Problem : Palindrome check.
 * Input   : One word.
 * Output  : true or false.
 * Approach: Recursion on indexes.
 * Time    : O(n)
 * Space   : O(n) call stack
 * Java    : 8 or newer.
 */
import java.util.Scanner;

public class Main {
        // Step 1: Check the part of the word from index left to index right.
        static boolean check(String s, int left, int right) {
            // Step 2: Base case. One letter or no letter is always a palindrome.
            if (left >= right) {
                return true;
            }

            // Step 3: If the outer letters differ, stop. Otherwise check the inside.
            if (s.charAt(left) != s.charAt(right)) {
                return false;
            }
            return check(s, left + 1, right - 1);
        }

    // This method solves the task. It receives the input and returns the answer.
    static boolean solve(String s) {
        return check(s, 0, s.length() - 1);
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String s = scanner.hasNextLine() ? scanner.nextLine() : "";
        System.out.println(solve(s));
    }
}