day 7 part 1

AdventOfCode/Day07.cs

@@ -0,0 +1,133 @@
+namespace AdventOfCode;
+
+public class Day07 : BaseDay
+{
+    private Hand[] _hands;
+
+    public Day07() 
+    {
+        _hands = File.ReadAllLines(InputFilePath).Select(Hand.Parse).ToArray();
+    }
+
+    public override ValueTask<string> Solve_1()
+    {
+        Array.Sort(_hands);
+
+        long result = 0;
+        for (int i = 0; i < _hands.Length; ++i)
+        {
+            result += _hands[i].Bid * (i + 1);
+        }
+
+        return new(result.ToString());
+    }
+
+    public override ValueTask<string> Solve_2()
+    {
+        return new("TBD");
+    }
+
+    private record Hand(string Cards, int Bid) : IComparable<Hand>
+    {
+        public HandType HandType { get; init; }
+
+        public static Hand Parse(string line)
+        {
+            string[] parts = line.Split(" ");
+            return new Hand(parts[0], int.Parse(parts[1]))
+            { 
+                HandType = GetHandType(parts[0])
+            };
+        }
+
+        private static HandType GetHandType(string cards)
+        {
+            Dictionary<char, int> dict = new Dictionary<char, int>();
+            foreach (char ch in cards)
+            {
+                dict[ch] = dict.ContainsKey(ch) ? dict[ch] + 1 : 1;
+            }
+
+            if (dict.Any(kv => kv.Value == 5))
+            {
+                return HandType.FiveOfAKind;
+            }
+            if (dict.Any(kv => kv.Value == 4))
+            {
+                return HandType.FourOfAKind;
+            }
+            if (dict.Any(kv => kv.Value == 3) && dict.Any(kv => kv.Value == 2))
+            {
+                return HandType.FullHouse;
+            }
+            if (dict.Any(kv => kv.Value == 3))
+            {
+                return HandType.ThreeOfAKind;
+            }
+            if (dict.Count(kv => kv.Value == 2) == 2)
+            {
+                return HandType.TwoPair;
+            }
+            if (dict.Count(kv => kv.Value == 2) == 1)
+            {
+                return HandType.OnePair;
+            }
+            return HandType.HighCard;
+        }
+
+        public int CompareTo(Hand other)
+        {
+            if (this.HandType < other.HandType)
+            {
+                return -1;
+            }
+            if (this.HandType > other.HandType)
+            {
+                return 1;
+            }
+
+            for (int i = 0; i < this.Cards.Length; ++i)
+            {
+                if (this.Cards[i] == other.Cards[i])
+                {
+                    continue;
+                }
+
+                Card a = (Card)Enum.Parse(typeof(Card), "_" + this.Cards[i].ToString());
+                Card b = (Card)Enum.Parse(typeof(Card), "_" + other.Cards[i].ToString());
+
+                return a - b;
+            }
+
+            return 0;
+        }
+    }
+
+    private enum HandType
+    {
+        HighCard = 1,
+        OnePair = 2,
+        TwoPair = 3,
+        ThreeOfAKind = 4,
+        FullHouse = 5,
+        FourOfAKind = 6,
+        FiveOfAKind = 7
+    }
+
+    private enum Card
+    {
+        _2 = 2,
+        _3 = 3,
+        _4 = 4,
+        _5 = 5,
+        _6 = 6,
+        _7 = 7,
+        _8 = 8,
+        _9 = 9,
+        _T = 10,
+        _J = 11,
+        _Q = 12,
+        _K = 13,
+        _A = 14
+    }
+}