图的代码实现：

1. 

    

2. package com.model.graph;
   
   import java.util.ArrayList;
   import java.util.Arrays;
   import java.util.List;
   
   /**
    * @Description:测试类
    * @Author: 张紫韩
    * @Crete 2021/7/17 15:16
    * 演示图的实现，图的快速入门
    */
   public class GraphDemo01 {
       public static void main(String[] args) {
           Graph graph = new Graph(5);
           graph.insertVertex("A");
           graph.insertVertex("B");
           graph.insertVertex("C");
           graph.insertVertex("D");
           graph.insertVertex("E");
           graph.addEdges(0, 1, 1);
           graph.addEdges(0, 2, 1);
           graph.addEdges(1, 2, 1);
           graph.addEdges(1, 3, 1);
           graph.addEdges(1, 4, 1);
           graph.showGraph();
   
       }
   }
   class Graph{
       private List<String> vertexList=null;//保存节点的list
       private int[][] edges=null;//保存边的矩阵
       private int numEdges=0;//边的数目
   
       public Graph(int n) {
           vertexList=new ArrayList<>(n);
           edges=new int[n][n];
           numEdges=0;
       }
   
       //    保存节点的值，第一个节点的名字
       public void insertVertex(String vertex){
           vertexList.add(vertex);
       }
   //    添加边
       public void addEdges(int v1,int v2,int weight){
           edges[v1][v2]=weight;
           edges[v2][v1]=weight;
           numEdges++;
       }
       public int getNumOfVertex(){
           return vertexList.size();
       }
       public int getNumEdges(){
           return numEdges;
       }
   //    返回节点的值，名字
       public String getVertex(int index){
           return vertexList.get(index);
       }
       public int getWeight(int v1,int v2){
           return edges[v1][v2];
       }
       public void showGraph(){
          for (int[] arr:edges){
              System.out.println(Arrays.toString(arr));
          }
       }
   
   }

图的遍历-深度优先（DFS）：

1. 

2. 

3. public void dfs(){
           for (int i = 0; i < getNumEdges(); i++) {
               if (!isVisited[i]){
                   dfs(isVisited, i);
               }
           }
   
       }
       //    深度优先算法
       private void dfs(boolean[] isVisited, int index) {
           isVisited[index] = true;
           System.out.print(vertexList.get(index)+"->");
           int neighbor = getFirstNeighbor(index);
           while (neighbor != -1) {
               if (!isVisited[neighbor]) {
                   dfs(isVisited, neighbor);
               }
               neighbor = getNextNeighbor(index, neighbor);
           }
   
   
       }

图的遍历-广度优先算法（BFS）:

1. 

2. 

3. //    广度优先遍历算法
       public void bfs(){
           isVisited = new boolean[getNumOfVertex()];
           for (int i = 0; i < isVisited.length; i++) {
               if (!isVisited[i]){
                   bfs(isVisited,i);
               }
           }
   
       }
       //    广度优先遍历算法
       public void bfs(boolean[] isVisited, int index){
           int u; //队列的头节点的小标
           int w;//邻接节点
           LinkedList queue=new LinkedList();//记录节点的访问顺序
           System.out.print(getVertex(index)+"->");
           isVisited[index]=true;
           queue.addLast(index);
           while(!queue.isEmpty()){
               u= (int) queue.removeFirst();
               w=getFirstNeighbor(u);
               while (w!=-1){
                   if (!isVisited[w]){
                       System.out.print(getVertex(w)+"->");
                       isVisited[w]=true;
                       queue.addLast(w);
                   }else {
                       w=getNextNeighbor(u, w);
                   }
               }
           }
   
       }

1. 

2.         Graph graph1 = new Graph(8);
           graph1.insertVertex("1");
           graph1.insertVertex("2");
           graph1.insertVertex("3");
           graph1.insertVertex("4");
           graph1.insertVertex("5");
           graph1.insertVertex("6");
           graph1.insertVertex("7");
           graph1.insertVertex("8");
           graph1.addEdges(0, 1, 1);
           graph1.addEdges(0, 2, 1);
           graph1.addEdges(1, 3, 1);
           graph1.addEdges(1, 4, 1);
           graph1.addEdges(3, 7, 1);
           graph1.addEdges(4, 7, 1);
           graph1.addEdges(2, 5, 1);
           graph1.addEdges(2, 6, 1);
           graph1.addEdges(5, 6, 1);
           graph1.showGraph();
           System.out.println("深度优先算法");
           graph1.dfs();
           System.out.println();
           System.out.println("广度优先算法");
           graph1.bfs();