AdventOfCode2017/Day25

Day25.java

public static HashMap<Integer, Boolean> checksum = new HashMap<Integer, Boolean>(); // Used to be Byte, changed to Boolean for performance

	public static void main(String args[]) throws IOException {

		int state = 0; // A, B, C, D, E, F
						// 0, 1, 2, 3, 4, 5

		int currentPos = 0;

		for (int i = 0; i < 12173597; i++) {
			System.out.println("Running " + i + " (State: " + state + ")");
			switch (state) {

			case 0:
				if (get(currentPos) == false) {
					print(currentPos, true);
					currentPos += 1;
					state = 1;
				} else {
					print(currentPos, false);
					currentPos += -1;
					state = 2;
				}
				break;
			case 1:
				if (get(currentPos) == false) {
					print(currentPos, true);
					currentPos += -1;
					state = 0;
				} else {
					print(currentPos, true);
					currentPos += 1;
					state = 3;
				}
				break;
			case 2:
				if (get(currentPos) == false) {
					print(currentPos, true);
					currentPos += 1;
					state = 0;
				} else {
					print(currentPos, false);
					currentPos += -1;
					state = 4;
				}
				break;
			case 3:
				if (get(currentPos) == false) {
					print(currentPos, true);
					currentPos += 1;
					state = 0;
				} else {
					print(currentPos, false);
					currentPos += 1;
					state = 1;
				}
				break;
			case 4:
				if (get(currentPos) == false) {
					print(currentPos, true);
					currentPos += -1;
					state = 5;
				} else {
					print(currentPos, true);
					currentPos += -1;
					state = 2;
				}
				break;
			case 5:
				if (get(currentPos) == false) {
					print(currentPos, true);
					currentPos += 1;
					state = 3;
				} else {
					print(currentPos, true);
					currentPos += 1;
					state = 0;
				}
				break;
			
			}
			
		}

		System.out.println(toString(checksum));
    System.out.println("Merry Christmas!");

	}

	public static void print(int pos, boolean toPrint) {
		
		checksum.put(pos, toPrint);
		
	}

	public static String toString(HashMap<Integer, Boolean> toAnalyse) {
		int i = 0;
		for(boolean c : toAnalyse.values()) {
			if(c == true) i++;
		}
		return i + "";

	}
	
	public static boolean get(int pos) {

		return checksum.getOrDefault(pos, false);
		
	}