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124 lines
3.1 KiB
JavaScript
124 lines
3.1 KiB
JavaScript
/**
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* File: graph_adjacency_list.js
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* Created Time: 2023-02-09
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* Author: Justin (xiefahit@gmail.com)
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*/
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/* 顶点类 */
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class Vertex {
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val;
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constructor(val) {
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this.val = val;
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}
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}
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/* 基于邻接表实现的无向图类 */
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class GraphAdjList {
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// 邻接表，使用哈希表来代替链表，以提升删除边、删除顶点的效率
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// 请注意，adjList 中的元素是 Vertex 对象
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adjList;
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/* 构造方法 */
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constructor(edges) {
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this.adjList = new Map();
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// 添加所有顶点和边
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for (const edge of edges) {
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this.addVertex(edge[0]);
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this.addVertex(edge[1]);
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this.addEdge(edge[0], edge[1]);
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}
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}
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/* 获取顶点数量 */
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size() {
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return this.adjList.size;
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}
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/* 添加边 */
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addEdge(vet1, vet2) {
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if (!this.adjList.has(vet1) || !this.adjList.has(vet2) || vet1 === vet2) {
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throw new Error("Illegal Argument Exception");
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}
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// 添加边 vet1 - vet2
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this.adjList.get(vet1).add(vet2);
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this.adjList.get(vet2).add(vet1);
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}
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/* 删除边 */
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removeEdge(vet1, vet2) {
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if (!this.adjList.has(vet1) || !this.adjList.has(vet2) || vet1 === vet2) {
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throw new Error("Illegal Argument Exception");
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}
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// 删除边 vet1 - vet2
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this.adjList.get(vet1).delete(vet2);
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this.adjList.get(vet2).delete(vet1);
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}
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/* 添加顶点 */
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addVertex(vet) {
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if (this.adjList.has(vet)) return;
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// 在邻接表中添加一个新链表
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this.adjList.set(vet, new Set());
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}
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/* 删除顶点 */
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removeVertex(vet) {
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if (!this.adjList.has(vet)) {
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throw new Error("Illegal Argument Exception");
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}
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// 在邻接表中删除顶点 vet 对应的链表
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this.adjList.delete(vet);
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// 遍历其它顶点的链表，删除所有包含 vet 的边
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for (let set of this.adjList.values()) {
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set.delete(vet);
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}
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}
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/* 打印邻接表 */
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print() {
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console.log("邻接表 =");
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for (const [key, value] of this.adjList) {
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const tmp = [];
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for (const vertex of value){
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tmp.push(vertex.val);
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}
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console.log(key.val + ": " + tmp + ",");
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}
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}
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}
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/* Driver Code */
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/* 初始化无向图 */
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const v0 = new Vertex(1),
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v1 = new Vertex(3),
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v2 = new Vertex(2),
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v3 = new Vertex(5),
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v4 = new Vertex(4);
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const edges = [[v0, v1], [v1, v2], [v2, v3], [v0, v3], [v2, v4], [v3, v4]];
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const graph = new GraphAdjList(edges);
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console.log("\n初始化后，图为");
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graph.print();
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/* 添加边 */
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// 顶点 1, 2 即 v0, v2
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graph.addEdge(v0, v2);
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console.log("\n添加边 1-2 后，图为");
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graph.print();
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/* 删除边 */
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// 顶点 1, 3 即 v0, v1
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graph.removeEdge(v0, v1);
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console.log("\n删除边 1-3 后，图为");
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graph.print();
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/* 添加顶点 */
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const v5 = new Vertex(6);
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graph.addVertex(v5);
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console.log("\n添加顶点 6 后，图为");
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graph.print();
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/* 删除顶点 */
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// 顶点 3 即 v1
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graph.removeVertex(v1);
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console.log("\n删除顶点 3 后，图为");
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graph.print();
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