增加了 RelationshipHelper.FindFragments 方法

Author: guogangj

AlgorithmLib/AlgorithmLib.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
-    <Version>1.0.2</Version>
+    <Version>1.0.3</Version>
     <PackageId>AlgorithmLib</PackageId>
     <Authors>Jiang Guogang</Authors>
     <Company></Company>

AlgorithmLib/ArrayHelper.cs

@@ -0,0 +1,46 @@
+using System;
+
+namespace AlgorithmLib {
+    public class ArrayHelper {
+
+        /// <summary>
+        /// 数组元素位移，子数组位移
+        /// </summary>
+        /// <param name="array">数组</param>
+        /// <param name="index">要位移的子数组的起始位置</param>
+        /// <param name="length">要位移的子数组的长度</param>
+        /// <param name="offset">位移量，正数表示向后移，负数表示向前移</param>
+        /// <remarks>
+        /// 越界会抛错，比如[1,2,3,4,5,6,7]，我要[5,6]向后位移2，则抛错
+        /// </remarks>
+        /// <exception cref="IndexOutOfRangeException">越界异常</exception>
+        public static void ShiftArrayItems<T>(T[] array, int index, int length, int offset) {
+            if (index < 0) {
+                throw new IndexOutOfRangeException("index不能小于0");
+            }
+            if (index + length > array.Length) {
+                throw new IndexOutOfRangeException("指定的子数组越界");
+            }
+            if (index + offset < 0 || index + length + offset > array.Length) {
+                throw new IndexOutOfRangeException("子数组位移越界");
+            }
+            if (length == 0 || offset == 0) {
+                return;
+            }
+
+            //将子数组Copy出来
+            T[] tempArray = new T[length];
+            Array.Copy(array, index, tempArray, 0, length);
+
+            if (offset > 0) {
+                
+                Array.Copy(array, index + length, array, index, offset);
+                Array.Copy(tempArray, 0, array, index + offset, length);
+            }
+            else {
+                Array.Copy(array, index + offset, array, index + offset + length, -offset);
+                Array.Copy(tempArray, 0, array, index + offset, length);
+            }
+        }
+    }
+}

AlgorithmLib/RelationshipHelper.cs

@@ -80,5 +80,37 @@ int[] SubFindRelationship(int currOriginalIdx, int matchedValForCurrOrgIdx, int[
 
             return SubFindRelationship(0, 0, fragments);
         }
+
+        /// <summary>
+        /// 找出能够合成整体的碎片集（这相当于是FindRelationship的“局部版”）
+        /// </summary>
+        /// <param name="whole">整体</param>
+        /// <param name="fragmentgs">碎片源</param>
+        /// <returns>返回null表示找不到合适的</returns>
+        public static int[] FindFragments(int whole, int[] fragments) {
+            int[] SubFindFragments(int subWhole, int[] subFragments) {
+                if (subFragments.Length == 1) {
+                    return subWhole == subFragments[0] ? subFragments : null;
+                }
+                HashSet<int> hash = new HashSet<int>();
+                for(int i=0; i<subFragments.Length; i++) {
+                    if (hash.Contains(subFragments[i])) {
+                        continue;
+                    }
+                    hash.Add(subFragments[i]);
+                    if (subWhole == subFragments[i]) {
+                        return new int[] { subFragments[i] };
+                    }
+                    else if (subWhole > subFragments[i]) {
+                        int[] res = SubFindFragments(subWhole - subFragments[i], RollArrayAndRemoveFirstByIndex(subFragments, i));
+                        if(res != null) {
+                            return PrependElementToArray(res, subFragments[i]);
+                        }
+                    }
+                }
+                return null;
+            }
+            return SubFindFragments(whole, fragments);
+        }
     }
 }

AlgorithmLibDemo/AlgorithmLibDemo.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <TargetFramework>net6.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>