Add Months to a Date

/*
 * Problem : Process a date.
 * Input   : One line of text.
 * Output  : The new date.
 * Approach: day month year k.
 * Time    : O(1)
 * Space   : O(1)
 * 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 String solve(String s) {
        // Step 1: Read day, month, year and the number of months to add.
        String[] part = s.trim().split("\\s+");
        int day = Integer.parseInt(part[0]);
        int month = Integer.parseInt(part[1]);
        int year = Integer.parseInt(part[2]);
        int shift = Integer.parseInt(part[3]);
        // Step 2: Count months from year 0. Then the shift is a plain addition. floorDiv works for negative values.
        int total = year * 12 + (month - 1) + shift;
        int newYear = Math.floorDiv(total, 12);
        int newMonth = Math.floorMod(total, 12) + 1;
        // Step 3: Find the length of the new month. February has 29 days in a leap year.
        boolean leap = (newYear % 4 == 0 && newYear % 100 != 0) || newYear % 400 == 0;
        int[] days = {31, leap ? 29 : 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
        // Step 4: Clamp the day to the length of the new month.
        return Math.min(day, days[newMonth - 1]) + " " + newMonth + " " + newYear;
    }

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