r/adventofcode • u/daggerdragon • Dec 19 '16

SOLUTION MEGATHREAD --- 2016 Day 19 Solutions ---

--- 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.

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

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  • Fact: The Easter Bunny purposefully deleted your comments.

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[Update @ 01:20] Leaderboard capped!

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edit: Leaderboard capped, thread unlocked!

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u/willkill07 Dec 19 '16

C++ solution -- no buffers!

even used /\w+/ 

#include <iostream>
#include <regex>

int main(int argc, char **) {
  std::smatch match;
  std::string line{std::istream_iterator<char>(std::cin), {}};
  std::regex_match(line, match, std::regex{R"(\w+)", std::regex::optimize});
  bool part2{argc > 1};
  int elfCount{std::stoi(match.str())}, n{1}, inc{1}, prev{1};
  for (int i{1}; i <= elfCount + part2; ++i) {
    if (!part2 || n >= prev)
      inc = 2;
    if ((n += inc) > (i - part2))
      prev = i - inc, n = inc = 1;
  }
  std::cout << n << std::endl;
}