Valid IPv4 Address

/*
 * Problem : Process one line of text.
 * Input   : One line of text.
 * Output  : true or false.
 * Approach: Check every part.
 * Time    : O(n)
 * Space   : O(n)
 * Java    : 8 or newer.
 */
import java.util.Scanner;

public class Main {
    // This method solves the task. It receives the input and returns the answer.
    static boolean solve(String s) {
        // Step 1: Split at the dots. The limit -1 keeps empty parts at the end.
        String[] parts = s.split("\\.", -1);

        // Step 2: There must be exactly four parts.
        if (parts.length != 4) {
            return false;
        }

        for (String part : parts) {
            // Step 3: Each part has 1 to 3 characters.
            if (part.length() == 0 || part.length() > 3) {
                return false;
            }

            // Step 4: Each character must be a digit.
            for (char c : part.toCharArray()) {
                if (c < '0' || c > '9') {
                    return false;
                }
            }

            // Step 5: No leading zeros, and the value is at most 255.
            if (part.length() > 1 && part.charAt(0) == '0') {
                return false;
            }
            if (Integer.parseInt(part) > 255) {
                return false;
            }
        }
        return true;
    }

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