3.2.43 Finished

Author: ikesnowy

3 Searching/3.2/3.2.43/3.2.43.csproj

@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <RootNamespace>_3._2._43</RootNamespace>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\BinarySearchTree\BinarySearchTree.csproj" />
+  </ItemGroup>
+
+</Project>

3 Searching/3.2/3.2.43/Program.cs

@@ -0,0 +1,34 @@
+using System;
+using BinarySearchTree;
+
+namespace _3._2._43
+{
+    class Program
+    {
+        static void Main(string[] args)
+        {
+            const int trials = 10;
+            var putTime = 0L;
+            var setTime = 0L;
+            for (var j = 0; j < trials; j++)
+            {
+                var random = new Random();
+                var bst = new BSTTimer<int, int>();
+                var data = new int[1000000];
+                for (var i = 0; i < data.Length; i++)
+                {
+                    data[i] = random.Next();
+                }
+
+                FrequencyCounter.MostFrequentlyKey(bst, data);
+                putTime += bst.PutTime;
+                setTime += bst.SetTime;
+            }
+
+            putTime /= trials;
+            setTime /= trials;
+            Console.WriteLine("Put: " + putTime + "ms Get: " + setTime + "ms ratio: " + (double)putTime / setTime);
+
+        }
+    }
+}

3 Searching/3.2/BinarySearchTree/BST.cs

@@ -115,7 +115,16 @@ protected virtual Node Put(Node x, TKey key, TValue value)
         /// </summary>
         /// <param name="key">需要查找的键。</param>
         /// <returns>找到的值，不存在则返回 <c>default(TValue)</c>。</returns>
-        public virtual TValue Get(TKey key) => Get(root, key).Value;
+        public virtual TValue Get(TKey key)
+        {
+            var result = Get(root, key);
+            if (result == null)
+            {
+                return default;
+            }
+
+            return result.Value;
+        }
 
         /// <summary>
         /// 递归查找 <paramref name="key"/> 所对应的结点。

3 Searching/3.2/BinarySearchTree/BSTTimer.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Diagnostics;
+
+namespace BinarySearchTree
+{
+    public class BSTTimer<TKey, TValue> : BST<TKey, TValue> where TKey : IComparable<TKey>
+    {
+        public long PutTime { get; set; }
+        public long SetTime { get; set; }
+
+        /// <summary>
+        /// 向二叉查找树中插入一个键值对。
+        /// </summary>
+        /// <param name="key">要插入的键。</param>
+        /// <param name="value">要插入的值。</param>
+        public override void Put(TKey key, TValue value)
+        {
+            var timer = Stopwatch.StartNew();
+            base.Put(key, value);
+            timer.Stop();
+            PutTime += timer.ElapsedMilliseconds;
+        }
+
+        /// <summary>
+        /// 获得 <paramref name="key"/> 对应的值，不存在则返回 <c>default(TValue)</c>。
+        /// </summary>
+        /// <param name="key">需要查找的键。</param>
+        /// <returns>找到的值，不存在则返回 <c>default(TValue)</c>。</returns>
+        public override TValue Get(TKey key)
+        {
+            var timer = Stopwatch.StartNew();
+            var result = base.Get(key);
+            timer.Stop();
+            SetTime += timer.ElapsedMilliseconds;
+            return result;
+        }
+    }
+}

3 Searching/3.2/BinarySearchTree/FrequencyCounter.cs

@@ -9,13 +9,8 @@ namespace BinarySearchTree
     /// 计算文本文档中出现次数最高的字符串，
     /// 用于测试符号表的 Get 和 Put 方法。
     /// </summary>
-    public class FrequencyCounter
+    public static class FrequencyCounter
     {
-        /// <summary>
-        /// 这个类不能被初始化。
-        /// </summary>
-        private FrequencyCounter() { }
-
         /// <summary>
         /// 计算数组中不重复元素的数量。
         /// </summary>

Algorithms 4th Edition.sln

@@ -1037,7 +1037,9 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "3.2.40", "3 Searching\3.2\3
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "3.2.41", "3 Searching\3.2\3.2.41\3.2.41.csproj", "{64038379-9705-4127-A25C-BC0391298EE0}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "3.2.42", "3 Searching\3.2\3.2.42\3.2.42.csproj", "{BAD1523D-5DE5-4117-9D57-C7A1F4A2A29A}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "3.2.42", "3 Searching\3.2\3.2.42\3.2.42.csproj", "{BAD1523D-5DE5-4117-9D57-C7A1F4A2A29A}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "3.2.43", "3 Searching\3.2\3.2.43\3.2.43.csproj", "{C17CA5CF-1E52-4330-8B1A-CB91AE537FCF}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -2853,6 +2855,10 @@ Global
 		{BAD1523D-5DE5-4117-9D57-C7A1F4A2A29A}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{BAD1523D-5DE5-4117-9D57-C7A1F4A2A29A}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{BAD1523D-5DE5-4117-9D57-C7A1F4A2A29A}.Release|Any CPU.Build.0 = Release|Any CPU
+		{C17CA5CF-1E52-4330-8B1A-CB91AE537FCF}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{C17CA5CF-1E52-4330-8B1A-CB91AE537FCF}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{C17CA5CF-1E52-4330-8B1A-CB91AE537FCF}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{C17CA5CF-1E52-4330-8B1A-CB91AE537FCF}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -3368,6 +3374,7 @@ Global
 		{28E56928-AA66-464E-B791-A72889D4C624} = {69512490-D514-490D-9088-D514FC5C770A}
 		{64038379-9705-4127-A25C-BC0391298EE0} = {69512490-D514-490D-9088-D514FC5C770A}
 		{BAD1523D-5DE5-4117-9D57-C7A1F4A2A29A} = {69512490-D514-490D-9088-D514FC5C770A}
+		{C17CA5CF-1E52-4330-8B1A-CB91AE537FCF} = {69512490-D514-490D-9088-D514FC5C770A}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {EE55CF8D-6F35-464D-B95B-ED85644AE41C}