133 lines
3.8 KiB
JavaScript
133 lines
3.8 KiB
JavaScript
/**
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* File: graph_adjacency_matrix.js
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* Created Time: 2023-02-09
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* Author: Zhuo Qinyue (1403450829@qq.com)
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*/
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/* Undirected graph class based on adjacency matrix */
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class GraphAdjMat {
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vertices; // Vertex list, elements represent "vertex value", index represents "vertex index"
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adjMat; // Adjacency matrix, row and column indices correspond to "vertex index"
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/* Constructor */
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constructor(vertices, edges) {
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this.vertices = [];
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this.adjMat = [];
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// Add vertex
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for (const val of vertices) {
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this.addVertex(val);
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}
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// Add edge
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// Please note, edges elements represent vertex indices, corresponding to vertices elements indices
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for (const e of edges) {
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this.addEdge(e[0], e[1]);
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}
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}
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/* Get the number of vertices */
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size() {
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return this.vertices.length;
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}
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/* Add vertex */
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addVertex(val) {
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const n = this.size();
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// Add new vertex value to the vertex list
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this.vertices.push(val);
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// Add a row to the adjacency matrix
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const newRow = [];
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for (let j = 0; j < n; j++) {
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newRow.push(0);
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}
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this.adjMat.push(newRow);
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// Add a column to the adjacency matrix
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for (const row of this.adjMat) {
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row.push(0);
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}
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}
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/* Remove vertex */
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removeVertex(index) {
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if (index >= this.size()) {
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throw new RangeError('Index Out Of Bounds Exception');
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}
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// Remove vertex at `index` from the vertex list
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this.vertices.splice(index, 1);
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// Remove the row at `index` from the adjacency matrix
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this.adjMat.splice(index, 1);
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// Remove the column at `index` from the adjacency matrix
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for (const row of this.adjMat) {
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row.splice(index, 1);
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}
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}
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/* Add edge */
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// Parameters i, j correspond to vertices element indices
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addEdge(i, j) {
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// Handle index out of bounds and equality
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if (i < 0 || j < 0 || i >= this.size() || j >= this.size() || i === j) {
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throw new RangeError('Index Out Of Bounds Exception');
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}
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// In an undirected graph, the adjacency matrix is symmetric about the main diagonal, i.e., (i, j) === (j, i)
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this.adjMat[i][j] = 1;
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this.adjMat[j][i] = 1;
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}
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/* Remove edge */
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// Parameters i, j correspond to vertices element indices
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removeEdge(i, j) {
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// Handle index out of bounds and equality
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if (i < 0 || j < 0 || i >= this.size() || j >= this.size() || i === j) {
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throw new RangeError('Index Out Of Bounds Exception');
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}
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this.adjMat[i][j] = 0;
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this.adjMat[j][i] = 0;
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}
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/* Print adjacency matrix */
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print() {
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console.log('Vertex list =', this.vertices);
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console.log('Adjacency matrix =', this.adjMat);
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}
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}
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/* Driver Code */
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/* Initialize undirected graph */
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// Please note, edges elements represent vertex indices, corresponding to vertices elements indices
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const vertices = [1, 3, 2, 5, 4];
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const edges = [
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[0, 1],
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[1, 2],
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[2, 3],
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[0, 3],
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[2, 4],
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[3, 4],
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];
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const graph = new GraphAdjMat(vertices, edges);
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console.log('\nAfter initialization, the graph is');
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graph.print();
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/* Add edge */
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// Indices of vertices 1, 2 are 0, 2 respectively
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graph.addEdge(0, 2);
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console.log('\nAfter adding edge 1-2, the graph is');
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graph.print();
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/* Remove edge */
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// Indices of vertices 1, 3 are 0, 1 respectively
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graph.removeEdge(0, 1);
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console.log('\nAfter removing edge 1-3, the graph is');
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graph.print();
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/* Add vertex */
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graph.addVertex(6);
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console.log('\nAfter adding vertex 6, the graph is');
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graph.print();
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/* Remove vertex */
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// Index of vertex 3 is 1
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graph.removeVertex(1);
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console.log('\nAfter removing vertex 3, the graph is');
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graph.print();
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