Refactored BestCombination.FindFrom2

SawCut/BestCombination.cs

@@ -6,99 +6,110 @@ namespace SawCut
     {
         public static BestComboResult FindFrom2(double length1, double length2, double stockLength)
         {
-            var result = new BestComboResult();
+            var result = InitializeResult(length1, length2);
-            result.Item1Length = length1;
-            result.Item2Length = length2;
-
             stockLength += Tolerance.Epsilon;
 
             if (length1 > stockLength)
             {
                 if (length2 > stockLength)
-                {
-                    //throw new Exception($"Either {nameof(length1)} or {nameof(length2)} must be less than or equal to the {nameof(stockLength)}");
                     return null;
-                }
 
-                result.Item1Count = 0;
+                return CalculateSingleItemResult(result, length2, stockLength, false);
-                result.Item2Count = (int)Math.Floor(stockLength / length2);
-                return result;
             }
-
+            else if (length2 > stockLength)
-            if (length2 > stockLength)
             {
-                result.Item1Count = (int)Math.Floor(stockLength / length1);
+                return CalculateSingleItemResult(result, length1, stockLength, true);
+            }
+            else
+            {
+                return CalculateOptimalCombination(result, length1, length2, stockLength);
+            }
+        }
+
+        private static BestComboResult InitializeResult(double length1, double length2)
+        {
+            return new BestComboResult
+            {
+                Item1Length = length1,
+                Item2Length = length2
+            };
+        }
+
+        private static BestComboResult CalculateSingleItemResult(BestComboResult result, double length, double stockLength, bool isItem1)
+        {
+            if (isItem1)
+            {
+                result.Item1Count = (int)Math.Floor(stockLength / length);
                 result.Item2Count = 0;
+            }
+            else
+            {
+                result.Item1Count = 0;
+                result.Item2Count = (int)Math.Floor(stockLength / length);
+            }
             return result;
         }
 
+        private static BestComboResult CalculateOptimalCombination(BestComboResult result, double length1, double length2, double stockLength)
+        {
             var maxCountLength1 = (int)Math.Floor(stockLength / length1);
-
             result.Item1Count = maxCountLength1;
             result.Item2Count = 0;
 
             var remnant = stockLength - maxCountLength1 * length1;
 
-            if (remnant.IsEqualTo(0))
-                return result;
-
             for (int countLength1 = 0; countLength1 <= maxCountLength1; ++countLength1)
             {
                 var remnant1 = stockLength - countLength1 * length1;
 
                 if (remnant1 >= length2)
-                {
+                    remnant = UpdateResultForTwoItems(result, length2, remnant1, remnant, countLength1);
-                    var countLength2 = (int)Math.Floor(remnant1 / length2);
-                    var remnant2 = remnant1 - length2 * countLength2;
-
-                    if (!(remnant2 < remnant))
-                        continue;
-
-                    result.Item1Count = countLength1;
-                    result.Item2Count = countLength2;
-
-                    if (remnant2.IsEqualTo(0))
-                        break;
-
-                    remnant = remnant2;
-                }
                 else
-                {
+                    remnant = UpdateResultForOneItem(result, remnant1, remnant, countLength1);
-                    if (!(remnant1 < remnant))
-                        continue;
 
-                    result.Item1Count = countLength1;
+                if (remnant.IsEqualTo(0))
-                    result.Item2Count = 0;
-
-                    if (remnant1.IsEqualTo(0))
                     break;
-
-                    remnant = remnant1;
-                }
             }
 
             return result;
         }
+
+        private static double UpdateResultForTwoItems(BestComboResult result, double length2, double remnant1, double currentRemnant, int countLength1)
+        {
+            var countLength2 = (int)Math.Floor(remnant1 / length2);
+            var remnant2 = remnant1 - countLength2 * length2;
+
+            if (remnant2 < currentRemnant)
+            {
+                result.Item1Count = countLength1;
+                result.Item2Count = countLength2;
+                return remnant2;
+            }
+
+            return currentRemnant;
+        }
+
+        private static double UpdateResultForOneItem(BestComboResult result, double remnant1, double currentRemnant, int countLength1)
+        {
+            if (remnant1 < currentRemnant)
+            {
+                result.Item1Count = countLength1;
+                result.Item2Count = 0;
+                return remnant1;
+            }
+
+            return currentRemnant;
+        }
     }
 
     public class BestComboResult
     {
         public double Item1Length { get; set; }
-
         public int Item1Count { get; set; }
-
+        public double Item1TotalLength => Item1Length * Item1Count;
-        public double Item1TotalLength
-        {
-            get { return Item1Length * Item1Count; }
-        }
 
         public double Item2Length { get; set; }
-
         public int Item2Count { get; set; }
-
+        public double Item2TotalLength => Item2Length * Item2Count;
-        public double Item2TotalLength
-        {
-            get { return Item2Length * Item2Count; }
-        }
     }
 }