Day 4: Scratchcards

Megathread guidelines

  • Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever)
  • Code block support is not fully rolled out yet but likely will be in the middle of the event. Try to share solutions as both code blocks and using something such as https://topaz.github.io/paste/ or pastebin (code blocks to future proof it for when 0.19 comes out and since code blocks currently function in some apps and some instances as well if they are running a 0.19 beta)

FAQ

🔒This post will be unlocked when there is a decent amount of submissions on the leaderboard to avoid cheating for top spots

🔓 Unlocked after 8 mins

    • @[email protected]English
      1•7 months ago

      Edit: Sorry, should have read your code first, you made it work too. if it works it works, Recursive solutions just click for me over other solutions.

      I made the recursion work, went to a depth of 24 for my input set.

      Recursive C# 
      internal class Day4Task2 : IRunnable
    {
        private Regex _regex = new Regex("Card\\s*\\d*: ([\\d\\s]{2} )*\\|( [\\d\\s]{2})*");
        private Dictionary _matchCountCache = new Dictionary();
        private int _maxDepth = 0;

        public void Run()
        {
            var inputLines = File.ReadAllLines("Days/Four/Day4Input.txt");
            int sumScore = 0;

            for (int i = 0; i < inputLines.Length; i++)
            {
                sumScore += ScoreCard(i, inputLines, 0);
                Console.WriteLine("!!!" + i + "!!!");
            }

            Console.WriteLine("Sum:"+sumScore.ToString());
            Console.WriteLine("Max Recursion Depth:"+ _maxDepth.ToString());
        }

        private int ScoreCard(int lineId, string[] inputLines, int depth)
        {
            if( depth > _maxDepth )
            {
                _maxDepth = depth;
            }

            if(lineId >= inputLines.Length)
            {
                return 0;
            }

            int matchCount = 0;

            if (!_matchCountCache.ContainsKey(lineId)) {

                var winningSet = new HashSet();
                var matches = _regex.Match(inputLines[lineId]);
                foreach (Capture capture in matches.Groups[1].Captures)
                {
                    winningSet.Add(capture.Value.Trim());
                }

                foreach (Capture capture in matches.Groups[2].Captures)
                {
                    if (winningSet.Contains(capture.Value.Trim()))
                    {
                        matchCount++;
                    }
                }

                _matchCountCache[lineId] = matchCount;
            }

            matchCount = _matchCountCache[lineId];

            int totalCards = 1;
            while(matchCount > 0)
            {
                totalCards += ScoreCard(lineId+matchCount, inputLines, depth+1);
                matchCount--;
            }
            //Console.WriteLine("Finished processing id: " + lineId + " Sum is: " + totalCards);
            return totalCards;
        }
    }