144 lines
3.6 KiB
C++
144 lines
3.6 KiB
C++
#pragma once
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#include <iostream>
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#include <cmath>
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#include "skipNode.h"
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template <class K, class E>
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class skipList {
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private:
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float cutOff; //确定层数
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int levels; //当前最大的非空链表
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int dSize; //字典的数对个数
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int maxLevel; //允许的最大链表层数
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K tailKey; //最大关键字
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skipNode<K, E>* headerNode; //头结点指针
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skipNode<K, E>* tailNode; //尾节点指针
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skipNode<K, E>** last; //last[i] 表示i层最后的节点
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public:
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skipList(K largeKey, int maxPairs, float prob); //构造
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std::pair<K, E>* find(const K& theKey) const; //用Key查找
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int level() const; //分级
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skipNode<K, E>* search(const K& theKey); //搜索并把每一级链表最后一个地址保存
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void insert(const std::pair<K, E>& thePair); //插入
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void erase(const K& theKey); //消除
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void showWholeList() const; //显示全部节点
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void showLv0List() const; //显示最底层节点（全部数据）
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};
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template<class K, class E>
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inline skipList<K, E>::skipList(K largeKey, int maxPairs, float prob)
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{
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cutOff = prob * RAND_MAX;
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maxLevel = (int)ceil(logf((float)maxPairs)) / logf(1 / prob) - 1;
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levels = 0;
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dSize = 0;
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tailKey = largeKey;
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std::pair<K, E> tailPair;
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tailPair.first = tailKey;
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headerNode = new skipNode<K, E>(tailPair, maxLevel + 1);
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tailNode = new skipNode<K, E>(tailPair, 0);
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last = new skipNode<K, E>* [maxLevel + 1];
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//链表空, headerNode = tailNode
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for (int i = 0; i <= maxLevel; i++) {
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headerNode->next[i] = tailNode;
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}
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}
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template<class K, class E>
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inline std::pair<K, E>* skipList<K, E>::find(const K& theKey) const
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{
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if (theKey >= tailKey) return nullptr;
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skipNode<K, E>* beforeNode = headerNode;
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for (int i = levels; i >= 0; i--) {
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while (beforeNode->next[i]->element.first < theKey) {
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beforeNode = beforeNode->next[i];
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}
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}
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if (beforeNode->next[0]->element.first == theKey) {
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return &beforeNode->next[0]->element;
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}
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return nullptr;
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}
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template<class K, class E>
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inline int skipList<K, E>::level() const
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{
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int lev = 0;
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while (rand() <= cutOff) lev++;
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return (lev <= maxLevel) ? lev : maxLevel;
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}
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template<class K, class E>
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inline skipNode<K, E>* skipList<K, E>::search(const K& theKey)
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{
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skipNode<K, E>* beforeNode = headerNode;
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for (int i = levels; i >= 0; i++) {
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while (beforeNode->next[i]->element.first < theKey) {
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beforeNode = beforeNode->next[i];
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}
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last[i] = beforeNode;
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}
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return beforeNode->next[0];
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}
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template<class K, class E>
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inline void skipList<K, E>::insert(const std::pair<K, E>& thePair)
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{
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if (thePair.first >= tailKey) {
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std::cout << "Key = " << thePair.first << " Must be < " << tailKey;
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}
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skipNode<K, E>* theNode = search(thePair.first);
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if (theNode->element.first == thePair.first) {
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theNode->element.second = thePair.second;
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return;
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}
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int theLevel = level();
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if (theLevel > levels) {
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theLevel = ++levels;
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last[theLevel] = headerNode;
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}
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skipNode<K, E>* newNode = new skipNode<K, E>(thePair, theLevel + 1);
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for (int i = 0; i <= theLevel; i++) {
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newNode->next[i] = last[i]->next[i];
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last[i]->next[i] = newNode;
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}
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dSize++;
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return;
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}
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template<class K, class E>
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inline void skipList<K, E>::erase(const K& theKey)
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{
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if (theKey >= tailKey) return;
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skipNode<K, E>* theNode = search(theKey);
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if (theNode->element.first != theKey) return;
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for (int i = 0; i <= levels && last[i]->next[i] == theNode; i++) {
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last[i]->next[i] = theNode->next[i];
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}
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while (levels > 0 && headerNode->next[levels] == tailNode) levels--;
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delete theNode;
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dSize--;
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}
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template<class K, class E>
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inline void skipList<K, E>::showLv0List() const
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{
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skipNode<K, E>* tmp = headerNode->next[0];
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while (tmp != tailNode) {
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std::cout << "{" << tmp->element.first << ", " << tmp->element.second << "}" << std::endl;
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tmp = tmp->next[0];
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}
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}
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