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