Initialized everything and completed Bucket.cs, Fire.cs, Well.cs.

BucketChain/Bucket.cs

@@ -5,7 +5,8 @@
 /// </summary>
 public sealed class Bucket
 {
-    // TODO
+    private readonly double _capacityLiters;
+    private double _contentLiters;
 
     /// <summary>
     ///     Creates a new bucket with the given capacity.
@@ -13,13 +14,14 @@ public sealed class Bucket
     /// <param name="capacityLiters">Bucket capacity in liters</param>
     public Bucket(double capacityLiters)
     {
-        // TODO
+        _capacityLiters = capacityLiters;
+        _contentLiters = 0D;
     }
 
     /// <summary>
     ///     Gets if this bucket is currently completely empty or not.
     /// </summary>
-    public bool IsEmpty => false; // TODO
+    public bool IsEmpty => _contentLiters <= 0D;
 
     /// <summary>
     ///     Fills the bucket to the brim if enough water is available.
@@ -30,8 +32,17 @@ public sealed class Bucket
     /// <returns>The amount taken for filling the bucket</returns>
     public double Fill(double maxAvailable)
     {
-        // TODO
-        return -1D;
+        if (_capacityLiters - _contentLiters <= 0D)
+        {
+            return 0D;
+        }
+
+        maxAvailable = Math.Abs(_capacityLiters - maxAvailable);
+        _contentLiters = _contentLiters + maxAvailable > _capacityLiters
+            ? _capacityLiters
+            : _contentLiters + maxAvailable;
+
+        return maxAvailable;
     }
 
     /// <summary>
@@ -40,7 +51,8 @@ public sealed class Bucket
     /// <returns>Amount emptied from the bucket, in liters</returns>
     public double Empty()
     {
-        // TODO
-        return -1D;
+        var content = _contentLiters;
+        _contentLiters = 0D;
+        return content;
     }
 }

BucketChain/Chain.cs

@@ -5,7 +5,12 @@
 /// </summary>
 public sealed class Chain
 {
-    // TODO
+    private readonly Fire _fire;
+    private readonly int _requiredPeople;
+    private readonly Well _well;
+    private readonly double _bucketSize;
+    private Person _firstPerson;
+    private int _availableBuckets;
 
     /// <summary>
     ///     Creates a new bucket chain based on the supplied parameters.
@@ -19,7 +24,12 @@ public sealed class Chain
     public Chain(int requiredPeople, int availableBuckets, double bucketSize, 
         Well well, Fire fire, Person firstPerson)
     {
-        // TODO
+        _requiredPeople = requiredPeople;
+        _availableBuckets = availableBuckets;
+        _bucketSize = bucketSize;
+        _well = well;
+        _fire = fire;
+        _firstPerson = firstPerson;
     }
 
     /// <summary>

BucketChain/Fire.cs

@@ -5,7 +5,7 @@
 /// </summary>
 public sealed class Fire
 {
-    // TODO
+    private readonly double _growRate;
 
     /// <summary>
     ///     Creates a new fire with the passed properties.
@@ -14,19 +14,19 @@ public sealed class Fire
     /// <param name="growRate">Rate by which the fire grows with each (chain operation) step</param>
     public Fire(double initialFireSize, double growRate)
     {
-        // TODO
+        _growRate = growRate;
+        FireSize = initialFireSize;
     }
 
     /// <summary>
     ///     Gets the current size of the fire; cannot be smaller than 0.
     /// </summary>
-    // TODO
-    // public double FireSize ...
+    public double FireSize { get; private set; }
 
     /// <summary>
     ///     Gets if the fire has been extinguished (= size is 0).
     /// </summary>
-    public bool Extinguished => false; // TODO
+    public bool Extinguished => FireSize <= 0D;
 
     /// <summary>
     ///     The fire is hit by a load of water from a bucket.
@@ -35,7 +35,7 @@ public sealed class Fire
     /// <param name="amount">Liters of water</param>
     public void GetHitByWater(double amount)
     {
-        // TODO
+        FireSize = FireSize - amount < 0D ? 0D : FireSize - amount;
     }
 
     /// <summary>
@@ -44,7 +44,7 @@ public sealed class Fire
     /// </summary>
     public void BurnHigher()
     {
-        // TODO
+        FireSize += _growRate;
     }
 
     /// <summary>
@@ -52,5 +52,5 @@ public sealed class Fire
     ///     The size is rounded to whole numbers.
     /// </summary>
     /// <returns>String representation of the fire</returns>
-    public override string ToString() => string.Empty; // TODO
+    public override string ToString() => $"🔥 {Math.Round(FireSize)}";
 }

BucketChain/Person.cs

@@ -5,7 +5,8 @@
 /// </summary>
 public sealed class Person
 {
-    // TODO
+    private Bucket? _backwardBucket;
+    private Bucket? _forwardBucket;
 
     /// <summary>
     ///     Creates a new person.
@@ -25,21 +26,18 @@ public sealed class Person
     /// <summary>
     ///     Gets the left neighbor of the person. Can be null.
     /// </summary>
-    // TODO
-    // public Person? LeftNeighbor ...
+    public Person? LeftNeighbor { get; private set; }
 
     /// <summary>
     ///     Gets the right neighbor of the person. Can be null.
     /// </summary>
-    // TODO
-    // public Person? RightNeighbor ...
+    public Person? RightNeighbor { get; private set; }
 
     /// <summary>
     ///     Gets the number of the last step in which this person performed a bucket move action.
     ///     Each person can only move, at most, once per step.
     /// </summary>
-    // TODO
-    // public int LastStepPerformed ...
+    public int LastStepPerformed { get; private set; }
 
     /// <summary>
     ///     The person joins an existing bucket chain at a specific position.

BucketChain/Well.cs

@@ -5,7 +5,8 @@
 /// </summary>
 public sealed class Well
 {
-    // TODO
+    private readonly double _maxCapacity;
+    private readonly double _refillRate;
 
     /// <summary>
     ///     Creates a new well with the supplied properties.
@@ -16,22 +17,24 @@ public sealed class Well
     ///     operation step</param>
     public Well(double maxCapacity, double refillRate)
     {
-        // TODO
+        _maxCapacity = maxCapacity;
+        _refillRate = refillRate;
     }
 
     /// <summary>
     ///     Gets how many liters currently remain in the well.
     ///     Cannot exceed the max. capacity of the well or drop below 0.
     /// </summary>
-    // TODO
-    // public double LitersRemaining ...
+    public double LitersRemaining { get; private set; }
 
     /// <summary>
     ///     Refills the well by the constant rate.
     /// </summary>
     public void Refill()
     {
-        // TODO
+        LitersRemaining = LitersRemaining + _refillRate > _maxCapacity
+            ? _maxCapacity
+            : LitersRemaining + _refillRate;
     }
 
     /// <summary>
@@ -42,7 +45,8 @@ public sealed class Well
     /// <param name="bucket">The bucket to fill</param>
     public void FillBucket(Bucket bucket)
     {
-        // TODO
+        var litersTaken = bucket.Fill(LitersRemaining);
+        LitersRemaining -= litersTaken;
     }
 
     /// <summary>
@@ -50,5 +54,5 @@ public sealed class Well
     ///     Shows the current and max. amount of liters - rounded to whole numbers.
     /// </summary>
     /// <returns>String representation of the well</returns>
-    public override string ToString() => string.Empty; // TODO
+    public override string ToString() => $"💧 {LitersRemaining}/{_maxCapacity}";
 }