66 lines
2.2 KiB
C#
66 lines
2.2 KiB
C#
// #define Day14
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#if Day14
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using System.Text.RegularExpressions;
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var text = File.ReadAllText("day14/input").Split("\n\n");
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var start = text[0].Select(x => x).ToList();
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var reg = new Regex(@"(?<a>\w)(?<b>\w) -> (?<res>\w)");
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var rules = reg.Matches(text[1]).Select(m => new Rule(new Pair(m.Groups["a"].Value[0], m.Groups["b"].Value[0]), m.Groups["res"].Value[0])).ToDictionary(x => x.p, x=> x.res);
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for (var i = 0; i < 10; i++) {
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var next = new List<char>();
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for (int pos = 1; pos < start.Count; pos++) {
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var res = rules[new Pair(start[pos - 1], start[pos])];
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next.Add(start[pos - 1]);
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next.Add(res);
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}
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next.Add(start.Last());
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start = next;
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}
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var charCountPartOne = start.GroupBy(s => s).ToDictionary(g => g.Key, g => g.LongCount());
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Console.WriteLine(charCountPartOne.Values.Max() - charCountPartOne.Values.Min());
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// Part two
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start = text[0].Select(x => x).ToList();
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int maxDepth = 40;
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var charCountPartTwo = new Dictionary<char, long>();
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var save = new Dictionary<AsKey, Dictionary<char, long>>();
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Dictionary<char, long> Process(Pair cur, int depth) {
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var curKey = new AsKey(cur, depth);
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if (save.ContainsKey(curKey)) {
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return save[curKey];
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}
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if (depth <= 0) {
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return new Dictionary<char, long>() { {cur.a, 1} };
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}
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var c = rules[cur];
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var first = Process(new Pair(cur.a, c), depth - 1);
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var second = Process(new Pair(c, cur.b), depth - 1);
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var merged = Merge(first, second);
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save[curKey] = merged.ToDictionary(x => x.Key, x => x.Value);
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return merged;
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}
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Dictionary<char, long> Merge(Dictionary<char, long> a, Dictionary<char, long> b) {
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return new List<Dictionary<char, long>>(){a, b}.SelectMany(x => x)
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.ToLookup(pair => pair.Key, pair => pair.Value)
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.ToDictionary(group => group.Key, group => group.Sum());
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}
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for (int pos = 1; pos < start.Count; pos++) {
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var countBla = Process(new Pair(start[pos - 1], start[pos]), maxDepth);
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charCountPartTwo = Merge(charCountPartTwo, countBla);
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}
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charCountPartTwo[start.Last()]++;
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Console.WriteLine(charCountPartTwo.Values.Max() - charCountPartTwo.Values.Min());
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record AsKey(Pair p, int depth);
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record Rule(Pair p, char res);
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record Pair(char a, char b);
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#endif |