feat(*): Add 2021-14 part 2 initial not efficient enough attempt files

2021/14/Program.cs

@@ -1,4 +1,6 @@
-namespace Day14
+using System.Diagnostics;
+
+namespace Day14
 {
     class Program
     {
@@ -7,8 +9,8 @@
             string[] lines = File.ReadAllLines("input.txt");
 
 
-            Part1(lines);
-            //Part2(lines);
+            //Part1(lines);
+            Part2(lines);
         }
 
         static void Part1(string[] lines)
@@ -62,6 +64,93 @@
             Console.WriteLine(mostCommon.count - leastCommon.count);
         }
 
+        static void Part2(string[] lines)
+        {
+            string polymerTemplate = lines[0];
+
+            Console.WriteLine($"Template: {polymerTemplate}");
+
+            // Pair insertion rules are stored from index 2 onwards
+            // A rule like AB -> C means that when elements A and B are immediately adjacent, element C
+            // should be inserted between them.
+            // Also, because all pairs are considered simultaneously, inserted elements are not considered
+            // to be part of a pair until the next step.
+
+            Dictionary<(char, char), char> rules = new Dictionary<(char, char), char>();
+            // Consider each rule
+            for (int i = 2; i < lines.Length; i++)
+            {
+                // e.g. AB -> C
+                string pairToMatch = lines[i].Substring(0, 2);
+                string characterToInsert = lines[i].Substring(6, 1);
+
+                rules.Add((pairToMatch[0], pairToMatch[1]), characterToInsert[0]);
+            }
+
+            // Set the number of steps to run
+            for (int i = 0; i < 40; i++)
+            {
+                Stopwatch stopWatch = new Stopwatch();
+                stopWatch.Start();
+                
+                CompleteStepNew(ref polymerTemplate, rules);
+
+                stopWatch.Stop();
+                TimeSpan ts = stopWatch.Elapsed;
+                string elapsedTime = String.Format("{0:00}:{1:00}:{2:00}.{3:00}",
+                    ts.Hours, ts.Minutes, ts.Seconds,
+                    ts.Milliseconds / 10);
+                Console.WriteLine($"Step {i + 1} took {elapsedTime}");
+            }
+
+            // Count occurrences of each character
+            char[] chars = polymerTemplate.ToCharArray();
+            List<char> uniqueCharacters = chars.Select(x => x).Distinct().ToList();
+            List<(char character, int count)> countList = new List<(char character, int count)>();
+
+            foreach (char character in uniqueCharacters)
+            {
+                countList.Add((character, polymerTemplate.Count(c => c == character)));
+            }
+
+            (char character, int count) mostCommon = countList.MaxBy(x => x.count);
+            (char character, int count) leastCommon = countList.MinBy(x => x.count);
+
+            Console.WriteLine(mostCommon.count - leastCommon.count);
+        }
+
+        static void CompleteStepNew(ref string polymerTemplate, Dictionary<(char, char), char> rules)
+        {
+            LinkedList<char> temporaryList = new LinkedList<char>();
+            char[] temporaryTemplate = polymerTemplate.ToCharArray();
+
+            for (int i = 0; i < temporaryTemplate.Length; i++)
+            {
+                temporaryList.AddLast(temporaryTemplate[i]);
+            }
+
+            LinkedListNode<char> pointer = temporaryList.Find(temporaryList.First());
+
+            // Insert the new character into the linked list but do not change the temporary template we're checking against
+            for (int i = 0; i < temporaryTemplate.Count() - 1; i++)
+            {
+                char insertValue;
+                rules.TryGetValue((temporaryTemplate[i], temporaryTemplate[i + 1]), out insertValue);
+
+                if (char.IsLetter(insertValue))
+                {
+                    temporaryList.AddAfter(pointer, insertValue);
+
+                    // Move on an extra position as we have added a node
+                    pointer = pointer.Next;
+                }
+
+                pointer = pointer.Next;
+            }
+
+            polymerTemplate = String.Join("", temporaryList);
+        }
+
         static void CompleteStep(ref string polymerTemplate, ref string[] lines, List<Rule> rules)
         {
             LinkedList<char> temporaryList = new LinkedList<char>();
@@ -94,6 +183,7 @@
             polymerTemplate = String.Join("", temporaryList);
         }
 
+
         class Rule
         {
             public char First { get; set; }