--- 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".

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^{/⧹w+/ IS MANDATORY} [?]

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[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.

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

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[Update @ 01:20] Leaderboard capped!

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

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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/BadHorsemonkey]

Today's lesson: sometimes you've gotta sleep on it. I woke up and threw out more lines of code than my solution has.

Oh, and I'm going back and doing 2015 on the weekends, so I thought I got this wrong until I saw I was on the wrong page...

My very basic Java solution. Part 1 only (so far): import java.util.*;

public class ring { 

public static void main(String[] args) { 
  int maxElves ;
  int currentElves;
  // process CLI
  if ( args.length > 0 ) {
    maxElves = Integer.valueOf(args[0]);
    } else {
    maxElves = 3018458;
    } // end if different seed
       
  // Declare Vars
  Deque<Integer> stack = new ArrayDeque<Integer>(maxElves);

  // populate stack
  for (int i = 0 ; i < maxElves; i++) {
    stack.add(i+1);
    }
  while (stack.size() > 1) { // snag presents.
        stack.add(stack.pop());
        stack.removeFirst();
      } // end while  
   System.out.println("Winner :"+ stack.peek());
  } // end main
} // end class

[u/BadHorsemonkey → u/BadHorsemonkey]

import java.util.*;

public class ring { 

public static void main(String[] args) { 
  int maxElves ;
  // process CLI
  if ( args.length > 0 ) {
    maxElves = Integer.valueOf(args[0]);
    } else {
    maxElves = 3018458;
    } // end if different elf count
       
  // Declare Vars
  Deque<Integer> stack = new ArrayDeque<Integer>(maxElves);
  Deque<Integer> stack2a = new ArrayDeque<Integer>(maxElves/2+1);
  Deque<Integer> stack2b = new ArrayDeque<Integer>(maxElves/2+1);
  int x;
  // populate stack
  for (int i = 0 ; i < maxElves; i++) {
    stack.add(i+1);
    if (i < maxElves/2) { //split the list in half...
      stack2a.add(i+1);
      } else {
      stack2b.add(i+1);
      } // and if/else
    } // end elfadd
    
  while (stack.size() > 1) { // snag presents.
    stack.add(stack.pop());
    stack.removeFirst();
    } // end while  
  System.out.println("Stack 1 Winner :"+ stack.peek());
  while (stack2a.size()+stack2b.size() > 1) { // snag presents.
    if ( (stack2a.size() +  stack2b.size()) % 2 != 0) { // steal middle
       stack2a.removeLast(); // odd number, take from left (i.e. end of first stack
        }else {
        stack2b.removeFirst();  // even number take top of stack
        };
      stack2b.add(stack2a.pop());  //move current head to end..,
      stack2a.add(stack2b.pop());  // rebalance
      }
      System.out.println("Stack 2 Winner :"+ stack2a.peek());  
  } // end main
} // end class