Problem 9. ** Points inside the House

import java.util.Locale;
import java.util.Scanner;


public class PointsInsideTheHouse {

	public static void main(String[] args) {

		Locale.setDefault(new Locale("en", "US"));
		Scanner input = new Scanner(System.in);

		double x = input.nextDouble();
		double y = input.nextDouble();

		double pointAX = 12.5;
		double pointAY = 8.5;

		double pointBX = 22.5;
		double pointBY = 8.5;

		double pointCX = 17.5;
		double pointCY = 3.5;

		double ABC = Math.abs(pointAX * (pointBY - pointCY) + pointBX * (pointCY - pointAY) + pointCX * (pointAY - pointBY));
		double ABP = Math.abs(pointAX * (pointBY - y) + pointBX * (y - pointAY) + x * (pointAY - pointBY));
		double APC = Math.abs(pointAX * (y - pointCY) + x * (pointCY - pointAY) + pointCX * (pointAY - y));
		double PBC = Math.abs(x * (pointBY - pointCY) + pointBX * (pointCY - y) + pointCX * (y - pointBY));
		boolean isInTriangle = ABP + APC + PBC == ABC;

		if (x >= 12.5 && x <= 22.5 && y >= 8.5 && y <= 13.5) {

			if (x > 17.5 && x < 20.0 && y > 8.5 && y < 13.5) {
				System.out.println("Outside");
			}else{
				System.out.println("Inside");
			}
		}else if(isInTriangle){
			System.out.println("Inside");
		}
		else{
			System.out.println("Outside");
		}
		input.close();
	}

}