cpp
#include <iostream>
#include <cstdlib>
#include <ctime>
#include <cstring>
const int MAX_LEVEL = 6;  // 最大层数

// 跳表节点模板
template<typename K, typename V>
struct SkipListNode {
    K key;
    V value;
    SkipListNode<K, V>** forward;

    SkipListNode(int level, const K& k, const V& v)
        : key(k), value(v) {
        forward = new SkipListNode<K, V>*[level + 1];
        memset(forward, 0, sizeof(SkipListNode<K, V>*) * (level + 1));
    }

    ~SkipListNode() {
        delete[] forward;
    }
};

// 跳表模板
template<typename K, typename V>
class SkipList {
public:
    SkipList() {
        head = new SkipListNode<K, V>(MAX_LEVEL, K(), V());
        level = 0;
        srand(time(NULL));  // 初始化随机数种子
    }

    ~SkipList() {
        SkipListNode<K, V>* p = head;
        while (p) {
            SkipListNode<K, V>* q = p;
            p = p->forward[0];
            delete q;
        }
    }

    // 查找键值对应的节点
    SkipListNode<K, V>* find(const K& key) const {
        SkipListNode<K, V>* p = head;
        for (int i = level; i >= 0; --i) {
            while (p->forward[i] && p->forward[i]->key < key) {
                p = p->forward[i];
            }
        }

        p = p->forward[0];
        if (p && p->key == key) {
            return p;
        } else {
            return nullptr;
        }
    }

    // 插入键值对
    void insert(const K& key, const V& value) {
        SkipListNode<K, V>* update[MAX_LEVEL + 1];
        memset(update, 0, sizeof(SkipListNode<K, V>*) * (MAX_LEVEL + 1));

        SkipListNode<K, V>* p = head;
        for (int i = level; i >= 0; --i) {
            while (p->forward[i] && p->forward[i]->key < key) {
                p = p->forward[i];
            }
            update[i] = p;
        }

        p = p->forward[0];
        if (p && p->key == key) {
            p->value = value;  // 键已存在，更新值
        } else {
            int newLevel = randomLevel();
            if (newLevel > level) {
                for (int i = level + 1; i <= newLevel; ++i) {
                    update[i] = head;
                }
                level = newLevel;
            }

            SkipListNode<K, V>* newNode = new SkipListNode<K, V>(newLevel, key, value);
            for (int i = 0; i <= newLevel; ++i) {
                newNode->forward[i] = update[i]->forward[i];
                update[i]->forward[i] = newNode;
            }
        }
    }

    // 删除键值对应的节点
    void remove(const K& key) {
        SkipListNode<K, V>* update[MAX_LEVEL + 1];
        memset(update, 0, sizeof(SkipListNode<K, V>*) * (MAX_LEVEL + 1));

        SkipListNode<K, V>* p = head;
        for (int i = level; i >= 0; --i) {
            while (p->forward[i] && p->forward[i]->key < key) {
                p = p->forward[i];
            }
           update[i] = p;
        }
        
        p = p->forward[0];
        if (p && p->key == key) {
            for (int i = 0; i <= level; ++i) {
                if (update[i]->forward[i] != p) {
                    break;
                }
                update[i]->forward[i] = p->forward[i];
            }
            delete p;
            
            while (level > 0 && head->forward[level] == nullptr) {
                --level;
            }
        }
    }

private:
    SkipListNode<K, V>* head;  // 头节点
    int level;  // 当前最大层数

    // 随机生成节点的层数
    int randomLevel() const {
        int newLevel = 0;
        while (rand() % 2 == 0 && newLevel < MAX_LEVEL) {
            ++newLevel;
        }
        return newLevel;
    }
};

// 示例使用
int main() {
    SkipList<int, std::string> skipList;

    // 插入键值对
    skipList.insert(1, "One");
    skipList.insert(2, "Two");
    skipList.insert(3, "Three");
    skipList.insert(4, "Four");
    skipList.insert(5, "Five");

    // 查找键值对应的节点
    SkipListNode<int, std::string>* node = skipList.find(3);
    if (node) {
        std::cout << "Value of key 3: " << node->value << std::endl;
    } else {
        std::cout << "Key 3 not found." << std::endl;
    }

    // 删除键值对应的节点
    skipList.remove(4);

    // 再次查找删除的节点
    node = skipList.find(4);
    if (node) {
        std::cout << "Value of key 4: " << node->value << std::endl;
    } else {
        std::cout << "Key 4 not found." << std::endl;
    }

    return 0;
}