96 lines
2.5 KiB
JavaScript
96 lines
2.5 KiB
JavaScript
/**
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* author dreamapplehappy
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* 关于代码的一些解释可以看一下这里：https://github.com/dreamapplehappy/blog/tree/master/2018/12/02
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*/
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const MAX_LEVEL = 16;
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class Node{
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data = -1;
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maxLevel = 0;
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refer = new Array(MAX_LEVEL);
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}
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class SkipList{
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levelCount = 1;
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head = new Node();
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static randomLevel() {
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let level = 1;
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for(let i = 1; i < MAX_LEVEL; i++) {
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if(Math.random() < 0.5) {
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level++;
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}
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}
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return level;
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}
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insert(value) {
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const level = SkipList.randomLevel();
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const newNode = new Node();
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newNode.data = value;
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newNode.maxLevel = level;
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const update = new Array(level).fill(new Node());
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let p = this.head;
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for(let i = level - 1; i >= 0; i--) {
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while(p.refer[i] !== undefined && p.refer[i].data < value) {
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p = p.refer[i];
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}
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update[i] = p;
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}
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for(let i = 0; i < level; i++) {
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newNode.refer[i] = update[i].refer[i];
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update[i].refer[i] = newNode;
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}
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if(this.levelCount < level) {
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this.levelCount = level;
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}
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}
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find(value) {
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if(!value){return null}
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let p = this.head;
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for(let i = this.levelCount - 1; i >= 0; i--) {
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while(p.refer[i] !== undefined && p.refer[i].data < value) {
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p = p.refer[i];
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}
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}
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if(p.refer[0] !== undefined && p.refer[0].data === value) {
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return p.refer[0];
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}
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return null;
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}
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remove(value) {
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let _node;
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let p = this.head;
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const update = new Array(new Node());
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for(let i = this.levelCount - 1; i >= 0; i--) {
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while(p.refer[i] !== undefined && p.refer[i].data < value){
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p = p.refer[i];
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}
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update[i] = p;
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}
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if(p.refer[0] !== undefined && p.refer[0].data === value) {
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_node = p.refer[0];
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for(let i = 0; i <= this.levelCount - 1; i++) {
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if(update[i].refer[i] !== undefined && update[i].refer[i].data === value) {
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update[i].refer[i] = update[i].refer[i].refer[i];
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}
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}
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return _node;
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}
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return null;
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}
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printAll() {
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let p = this.head;
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while(p.refer[0] !== undefined) {
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// console.log(p.refer[0].data)
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p = p.refer[0];
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}
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}
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}
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