图-邻接矩阵

/**
 * 模拟实现一个无向图
 */
class UndirectedVertexGraph {
    constructor(size){
        this.size = size;
        this.vertexesList = []; // 保存顶点
        this.edgeMatex = new Array(10).fill(0).map(() => new Array(10).fill(0)); // 用来保存邻接矩阵
        this.vertexes = 0; // 保存顶点数量
        this.edges = 0; // 保存边的数量
    }

    edgeSize() {
        return this.vertexes;
    }
    // 添加顶点
    addVertex(vertex) {
        this.vertexesList.push(vertex);
        this.vertexes++;
    }
    // 新增一条边
    addEdge(from, to, weight = 1) {
        const i = this.vertexesList.indexOf(from);
        const j = this.vertexesList.indexOf(to);
        this.edgeMatex[i][j] = weight;
        this.edgeMatex[j][i] = weight;
        this.edges++;
    }

    // 删除一条边
    removeEdge() {
        const i = this.vertexesList.indexOf(from);
        const j = this.vertexesList.indexOf(to);
        this.edgeMatex[i][j] = 0;
        this.edgeMatex[j][i] = 0;
        this.edges--;
    }

    // 删除一个顶点
    removeVertex(v) {
        const index = this.vertexesList.indexOf(v);

        for(let i = 0; i < this.vertexes; i++) {
            if(this.edgeMatex[index][i] !== 0) { // 表示index与i之间有一条边
                this.edges--;
            }
        }
        this.vertexesList.splice(index, 1);

        // index后面的所有行前移一行
        for(let i = index; i < this.vertexes - 1; i++) {
            for(let j = 0; j < this.vertexes; j++) {
                this.edgeMatex[i][j] = this.edgeMatex[i + 1][j];
            }
        }
        // index后面的所有列迁移一列
        for(let i = 0; i < this.vertexes; i++) {
            for(let j = index; j < this.vertexes - 1; j++) {
                this.edgeMatex[i][j] = this.edgeMatex[i][j + 1];
            }
        }
        this.vertexes--;


    }
    // 某个顶点的度
    degree(v) {
        const index = this.vertexesList.indexOf(v);
        let count = 0;
        for(let i = 0; i < this.vertexes; i++) {
            if(this.edgeMatex[index][i] !== 0) {
                count++;
            } 
        }
        return count;
    }



    // 显示图
    displayGraph() {
        console.log('这是一个无向图，领接矩阵');
        console.log('顶点信息', this.vertexesList); 
        for(let i = 0; i < this.vertexes; i++) {
            let str = ''
            for(let j = 0; j < this.vertexes; j++){
                str += this.edgeMatex[i][j] + ' ';
            }
            console.log(str);
        }
    }
}


const graph = new UndirectedVertexGraph(10);
graph.addVertex('A');
graph.addVertex('B');
graph.addVertex('C');
graph.addVertex('D');
graph.addVertex('E');
graph.addVertex('F');
console.log(graph, 'graph')

graph.addEdge('A', 'B');
graph.addEdge('A', 'D');
graph.addEdge('B', 'C');
graph.addEdge('B', 'E');
graph.addEdge('C', 'D');
graph.addEdge('C', 'F');
graph.addEdge('D', 'F');
graph.addEdge('E', 'F');    

graph.displayGraph()

// graph.removeVertex('B');

// graph.displayGraph()

console.log(graph.degree('B'), '----')