Days 15 and 16

Author: ilkkanummi

16.txt

@@ -0,0 +1,26 @@
+public class Day15 {
+
+	public static void main(String[] args) throws java.io.IOException {
+		long count1 = 0, gen1 = 703L, gen2 = 516L;
+		for (int i = 0; i < 40000000; i++) {
+			gen1 = next(true, true, gen1);
+			gen2 = next(true, false, gen2);
+			if ((gen1 & 0xffff) == (gen2 & 0xffff)) count1++;
+		}
+		System.out.print(count1);
+		count1 = 0; gen1 = 703L; gen2 = 516L;
+		for (int i = 0; i < 5000000; i++) {
+			gen1 = next(false, true, gen1);
+			gen2 = next(false, false, gen2);
+			if ((gen1 & 0xffff) == (gen2 & 0xffff)) count1++;
+		}
+		System.out.println(" - " + count1);
+	}
+
+	private static long next(boolean part1, boolean a, long curr) {
+		do curr = (curr * (a ? 16807 : 48271)) % 2147483647;
+		while (part1 ? false : curr % (a ? 4 : 8) != 0);
+		return curr;
+	}
+
+}

Day15.java

@@ -0,0 +1,40 @@
+public class Day16 {
+
+	public static void main(String[] args) throws java.io.IOException {
+		java.util.List<String> start = java.util.Arrays.asList("abcdefghijklmnop".split(""));
+		java.util.List<String> progs = new java.util.ArrayList<>(java.util.Arrays.asList("abcdefghijklmnop".split("")));
+		String[] rows = java.nio.file.Files.readAllLines(java.nio.file.Paths.get("16.txt")).get(0).split(",");
+		for (int k = 0; k < 1000000000; k++) {
+			if (k == 1) {
+				System.out.print(progs.toString().replaceAll(", ", ""));
+			}
+			if (k > 0 && progs.equals(start)) {
+				k = 1000000000 - (1000000000 % k);
+			}
+			for (String row : rows) {
+				if (row.charAt(0) == 'x') {
+					Integer pos1 = Integer.valueOf(row.substring(1).split("/")[0]);
+					Integer pos2 = Integer.valueOf(row.substring(1).split("/")[1]);
+					String tmp = progs.get(pos1);
+					progs.set(pos1, progs.get(pos2));
+					progs.set(pos2, tmp);
+				}
+				if (row.charAt(0) == 'p') {
+					int pos1 = progs.indexOf(String.valueOf(row.substring(1).split("/")[0].charAt(0)));
+					int pos2 = progs.indexOf(String.valueOf(row.substring(1).split("/")[1].charAt(0)));
+					String tmp = progs.get(pos1);
+					progs.set(pos1, progs.get(pos2));
+					progs.set(pos2, tmp);
+				}
+				if (row.charAt(0) == 's') {
+					for (int i = 0; i < Integer.valueOf(row.substring(1)); i++) {
+						progs.add(0, progs.get(progs.size() - 1));
+						progs.remove(progs.size() - 1);
+					}
+				}
+			}
+		}
+		System.out.println(" - " + progs.toString().replaceAll(", ", ""));
+	}
+
+}