add file

Author: weimaolong

hash_tree.cpp

@@ -0,0 +1,174 @@
+/*
+******************************************************************************
+* Copyright (c) 2016 Tencent Inc. All rights reserved
+* Author: [email protected]
+* Date: 2016-10-30
+* Description: 哈希树 - 质数分辨定理实现
+******************************************************************************
+*/
+
+template <class KeyType, class ValueType, int SIZE = 32>
+class HashTree
+{
+    struct Node
+    {
+        Node() : occupied_(false), child_({0}) {}
+        KeyType key_;
+        ValueType value_;
+        bool occupied_;
+        Node *child_[SIZE];
+    };
+
+public:
+    HashTree()
+    {
+        max_level_ = 0;
+        prime_ = {0};
+
+        for (int i = 2; i <= SIZE; ++i)
+        {
+            if (IsPrime(i))
+            {
+                prime_[++max_level_] = i;
+            }
+        }
+    }
+
+    /**
+     * 插入函数
+     * @param key 键
+     * @param value 值
+     * @return 成功 true, 失败 false
+     */
+    bool Insert(const KeyType &key,  const ValueType &value)
+    {
+        return Insert(&root_, 1, key, value);
+    }
+
+    /**
+     * 查找函数
+     * @param key 键
+     * @return 指向value的指针, 找不到时为NULL
+     */
+    const ValueType *Find(const KeyType &key)
+    {
+        return Find(&root_, 1, key);
+    }
+
+    /**
+     * 删除函数
+     * @param key 键
+     * @return 任何情况下都返回true
+     */
+    bool Delete(const KeyType &key)
+    {
+        return Delete(&root_, 1, key);
+    }
+
+private:
+    bool Insert(Node *node, int level, const KeyType &key, const ValueType &value)
+    {
+        if (!node->occupied_)
+        {
+            node->key_ = key;
+            node->value_ = value;
+            node->occupied_ = true;
+            return true;
+        }
+
+        if (level > max_level_)
+        {
+            return false;
+        }
+
+        int idx = key % prime_[level];
+
+        if (!node->child_[idx])
+        {
+            node->child_[idx] = new Node;
+        }
+
+        return Insert(node->child_[idx], ++level, key, value);
+    }
+
+    const ValueType *Find(Node *node, int level, const KeyType &key)
+    {
+        if (node->occupied_)
+        {
+            if (node->key_ == key)
+            {
+                return &node->value_;
+            }
+        }
+
+        int idx = key % prime_[level];
+        if (!node->child_[idx])
+        {
+            return 0;
+        }
+
+        return Find(node->child_[idx], ++level, key);
+    }
+
+    bool Delete(Node *node, int level, const KeyType &key)
+    {
+        if (node->occupied_)
+        {
+            if (node->key_ == key)
+            {
+                node->occupied_ = false;
+                return true;
+            }
+        }
+
+        int idx = key % prime_[level];
+        if (!node->child_[idx])
+        {
+            return true;
+        }
+
+        return Delete(node->child_[idx], ++level, key);
+    }
+public:
+    bool IsPrime(int n)
+    {
+        for (int i = 2; (i * i) < (n + 1); ++i)
+        {
+            if (!(n % i))
+            {
+                return false;
+            }
+        }
+        return true;
+    }
+
+private:
+    Node root_;
+    int  max_level_;
+    int  prime_[SIZE+1];
+};
+
+
+#include <iostream>
+
+int main()
+{
+    HashTree<int, std::string> tree;
+
+    tree.Insert(1111, "AAA");
+    tree.Insert(2222, "BBB");
+
+    const std::string *value;
+
+    value = tree.Find(2222);
+    std::cout << (value ? *value : "NULL") << std::endl;
+
+    tree.Delete(2222);
+
+    value = tree.Find(2222);
+    std::cout << (value ? *value : "NULL") << std::endl;
+
+    std::cout << tree.IsPrime(3);
+
+    return 0;
+}