Add solution for 2018/day07/part2

Author: suve

2018/day07/timed-steps.cs

@@ -0,0 +1,168 @@
+using System;
+using System.Collections.Generic;
+
+namespace AdventOfCode
+{
+	class Step
+	{
+		public char name;
+		public int? timeUntilDone;
+		public Dictionary<char, Step> requirements;
+		public Dictionary<char, Step> descendants;
+		
+		public void AddRequirement(Step req)
+		{
+			Step entry;
+			this.requirements.TryGetValue(req.name, out entry);
+			if(entry == null) this.requirements[req.name] = req;
+		}
+		
+		public void AddDescendant(Step desc)
+		{
+			Step entry;
+			this.descendants.TryGetValue(desc.name, out entry);
+			if(entry == null) this.descendants[desc.name] = desc;
+		}
+		
+		public void RemoveRequirement(Step req)
+		{
+			this.requirements.Remove(req.name);
+		}
+		
+		public void RemoveDescendant(Step desc)
+		{
+			this.descendants.Remove(desc.name);
+		}
+		
+		public Step(char theName)
+		{
+			this.name = theName;
+			this.requirements = new Dictionary<char, Step>();
+			this.descendants = new Dictionary<char, Step>();
+			this.timeUntilDone = null;
+		}
+	}
+	
+	class Day07 
+	{
+		private static Dictionary<char, Step> steps = new Dictionary<char, Step>();
+		
+		private static Step GetStep(char name)
+		{
+			Step step;
+			Day07.steps.TryGetValue(name, out step);
+			if(step == null)
+			{
+				step = new Step(name);
+				Day07.steps[name] = step;
+			}
+			
+			return step;
+		}
+		
+		private static void ReadInput()
+		{
+			string line;
+			while((line = Console.ReadLine()) != null)
+			{
+				string[] words = line.Split(" ".ToCharArray());
+				if(words.Length < 8) continue;
+				
+				char nameR = words[1].ToCharArray()[0];
+				char nameD = words[7].ToCharArray()[0];
+				
+				Step stepR = Day07.GetStep(nameR);
+				Step stepD = Day07.GetStep(nameD);
+				
+				stepR.AddDescendant(stepD);
+				stepD.AddRequirement(stepR);
+			}
+		}
+		
+		private static Step GetNextAvailableStep()
+		{
+			Step best = null;
+			foreach(KeyValuePair<char, Step> entry in Day07.steps)
+			{
+				if(entry.Value.requirements.Count > 0) continue;
+				if(entry.Value.timeUntilDone != null) continue;
+				
+				if(best != null)
+				{
+					if(best.name < entry.Value.name) continue;
+				}
+				
+				best = entry.Value;
+			}
+			
+			return best;
+		}
+		
+		private static void AdvanceSteps()
+		{
+			foreach(KeyValuePair<char, Step> entry in Day07.steps)
+			{
+				if(entry.Value.timeUntilDone == null) continue;
+				entry.Value.timeUntilDone -= 1;
+			}
+		}
+		
+		private static Step GetNextFinishedStep()
+		{
+			Step best = null;
+			foreach(KeyValuePair<char, Step> entry in Day07.steps)
+			{
+				if(entry.Value.timeUntilDone != 0) continue;
+				
+				if(best != null)
+				{
+					if(best.name < entry.Value.name) continue;
+				}
+				
+				best = entry.Value;
+			}
+			
+			return best;
+		}
+		
+		static void Main() 
+		{
+			Day07.steps = new Dictionary<char, Step>();
+			Day07.ReadInput();
+			
+			int extraTime = 60;
+			int workerLimit = 5;
+			
+			int simultaneousSteps = 0;
+			int totalTime = 0;
+			while(Day07.steps.Count > 0)
+			{
+				Step s;
+				while( (simultaneousSteps < workerLimit) && ((s = Day07.GetNextAvailableStep()) != null) ) 
+				{
+					Console.Write(s.name);
+					s.timeUntilDone = extraTime + (Convert.ToByte(s.name) - Convert.ToByte('A') + 1);
+					simultaneousSteps += 1;
+				}
+				
+				Day07.AdvanceSteps();
+				
+				while((s = Day07.GetNextFinishedStep()) != null)
+				{
+					Day07.steps.Remove(s.name);
+					foreach(KeyValuePair<char, Step> entry in s.descendants)
+					{
+						entry.Value.RemoveRequirement(s);
+					}
+					
+					simultaneousSteps -= 1;
+				}
+				
+				totalTime += 1;
+			}
+			
+			Console.WriteLine("");
+			Console.WriteLine("Part 2 time: " + totalTime);
+		}
+	}
+}

README.md

@@ -19,6 +19,7 @@ and some of it would get me kicked out of a job interview on the grounds of bein
 | 04 | [strategy.php](2018/day04/strategy.php)             | [strategy.php](2018/day04/strategy.php)       |
 | 05 | [polymer.php](2018/day05/polymer.php)               | [polymer.php](2018/day05/polymer.php)         |
 | 06 | [flood.c](2018/day06/flood.c)                       | [flood.c](2018/day06/flood.c)                 |
+| 07 | [lotsa-steps.cs](2018/day07/lotsa-steps.cs)         | [timed-steps.cs](2018/day07/lotsa-steps.cs)   |
 
 
 # 2017