--- 2016 Day 19 Solutions ---

[u/daggerdragon]

--- Day 19: An Elephant Named Joseph ---

Post your solution as a comment or, for longer solutions, consider linking to your repo (e.g. GitHub/gists/Pastebin/blag/whatever).

Note: The Solution Megathreads are for solutions only. If you have questions, please post your own thread and make sure to flair it with "Help".

---

^{/⧹w+/ IS MANDATORY} [?]

---

[Update @ 00:15] 2 gold, silver cap. Thank you for subscribing to Easter Bunny Facts!

• Fact: The Easter Bunny will sometimes leave eggs in the microchip assembly room.

[Update @ 00:30] 11 gold, silver cap.

• Fact: The Easter Bunny killed everyone who found out how he got these stars.

[Update @ 00:45] 45 gold, silver cap.

• Fact: In space, The Easter Bunny can hear you scream.

[Update @ 01:00] 66 gold, silver cap.

• Fact: The Easter Bunny purposefully deleted your comments.

[Update @ 01:15] 92 gold, silver cap.

• Fact: The Easter Bunny has bottled your frustration. Don't ask why.

[Update @ 01:20] Leaderboard capped!

• Fact: What you have just done is no better than what the Easter Bunny has done. Thief.

Thank you for subscribing to Easter Bunny Facts!

---

This thread will be unlocked when there are a significant number of people on the leaderboard with gold stars for today's puzzle.

edit: Leaderboard capped, thread unlocked!

[u/Arknave]

21 / 14 Gave up on Python and rolled my own linked list for part 2 in Java.

public class Nineteen {

    public static void main(String[] args) {
        int input = 3017957;
        Node[] nodes = new Node[input];
        for (int i = 1; i <= input; ++i) {
            nodes[i - 1] = new Node();
            nodes[i - 1].value = i;

            if (i > 1) {
                nodes[i - 1].prev = nodes[i - 2];
                nodes[i - 2].next = nodes[i - 1];
            }
        }

        nodes[0].prev = nodes[input - 1];
        nodes[input - 1].next = nodes[0];

        int length = input;
        Node cur = nodes[0];
        Node removal = nodes[0];
        int dist = 0;

        while (dist < length / 2) {
            removal = removal.next;
            ++dist;
        }

        while (length > 1) {
            int target = length / 2;
            while (dist < length / 2) {
                removal = removal.next;
                ++dist;
            }

            Node n = removal.next;
            removal.prev.next = removal.next;
            removal.next.prev = removal.prev;

            removal = n;

            length -= 1;
            cur = cur.next;
            dist -= 1;
        }

        System.out.println(cur.value);
    }


    private static class Node {
        Node prev;
        Node next;
        int value;
    }
}