AdventOfCode2017/Day10

Day10Part1.java

	List<String> bloccs = Files.readAllLines(Paths.get(new File("res/day10").getPath())).stream()
				.collect(Collectors.toList());

		String x = bloccs.get(0).trim();

		String[] lengths = x.split(",");
		int[] array = IntStream.range(0, 256).toArray();
		int skipSize = 0;
		int currentPos = 0;

		for (String s : lengths) {
			int i = Integer.parseInt(s);
			int cut = 0;

			int[] temp = new int[i];

			if (i <= array.length - currentPos) {
				cut = i;
			} else {
				cut = array.length - currentPos;
			}
			int leftover = i - cut;
			System.out.println(currentPos + " / " + i);
			System.arraycopy(array, currentPos, temp, 0, cut);
			System.arraycopy(array, 0, temp, cut, leftover);

			ArrayUtils.reverse(temp);

			System.arraycopy(temp, 0, array, currentPos, cut);
			System.arraycopy(temp, i - leftover, array, 0, leftover);

			currentPos += (i + skipSize);
			currentPos %= array.length;
			skipSize++;

		}

		System.out.println(array[0] * array[1]);

	}

Day10Part2.java

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

		List<String> bloccs = Files.readAllLines(Paths.get(new File("res/day10").getPath())).stream()
				.collect(Collectors.toList());

		String x = bloccs.get(0).trim();

		int[] lengths = toAscii(x);
		int[] array = IntStream.range(0, 256).toArray();
		int[] ascii = new int[255];
		
		int skipSize = 0;
		int currentPos = 0;
		
		for(int i1 = 0; i1 < 64; i1++) {
			for (int i : lengths) {
				
				int cut = 0;

				int[] temp = new int[i];

				if (i <= array.length - currentPos) {
					cut = i;
				} else {
					cut = array.length - currentPos;
				}
				int leftover = i - cut;
				System.out.println(currentPos + " / " + i);
				System.arraycopy(array, currentPos, temp, 0, cut);
				System.arraycopy(array, 0, temp, cut, leftover);

				ArrayUtils.reverse(temp);

				System.arraycopy(temp, 0, array, currentPos, cut);
				System.arraycopy(temp, i - leftover, array, 0, leftover);

				currentPos += (i + skipSize);
				currentPos %= array.length;
				skipSize++;

			}
		}
		
		int[] result = new int[16];
		
		for(int a = 0; a < 16; a++) {
			for(int b = 0; b < 16; b++) {
				result[a] ^= array[a * 16 + b];
			}
		}
		
		StringBuilder sb = new StringBuilder();
		
		for(int i : result) {
			String toAppend = Integer.toString(i, 16);
			
			sb.append(toAppend.length() == 1 ? '0' + toAppend : toAppend);
		}
		

		System.out.println(sb.toString());

	}
	

	private static int[] toAscii(String src) {
		int[] toAdd = {17, 31, 73, 47, 23};
		return ArrayUtils.addAll(src.chars().toArray(), toAdd);
		
	}