(HW)DFS and BFS(Java)

import java.util.HashMap;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Stack;

public class task1
{
    public static void main(String[] args)
    {    
        Graph g = new Graph(5);
        g.createGraph();
        
        System.out.println("DFS(递归)");
        DFS(g, 0);
        System.out.println();
        for(Vertex p : g.vertex) //数组元素的拷贝
            p.isvisited = false;
        System.out.println("DFS(迭代)");
        DFS_iterative(g, 0);
        for(Vertex p : g.vertex)
            p.isvisited = false;
        System.out.print('\n' + "BFS" + '\n');
        BFS(g, 0);
    }
    
    //递归
    public static void DFS(Graph g, int index)
    {
        System.out.print(g.vertex[index].name + " ");
        g.vertex[index].isvisited = true;
        
        for(Vertex v : g.adjacencyMap.get(g.vertex[index]))
            if(v.isvisited == false)
            {
                int i = g.locateVex(v.name);
                DFS(g, i);
            }
    }
    
    //非递归
    public static void DFS_iterative(Graph g, int index)
    {
        Stack<Vertex> stack = new Stack<>();
        stack.push(g.vertex[index]);
        Vertex p;
        
        while(!stack.isEmpty())
        {
            p = stack.pop();
            if(p.isvisited == false)
            {
                System.out.print(p.name + " ");
                p.isvisited = true;
                for(Vertex q : g.adjacencyMap.get(p))
                    if(q.isvisited == false)  //可避免重复入栈
                        stack.push(q); 
            }
        }
    }
    
    //BFS
    public static void BFS(Graph g, int index)
    {
        Queue<Vertex> queue = new LinkedList<>();
        Vertex p;
        System.out.print(g.vertex[index].name + " ");
        g.vertex[index].isvisited = true;
        queue.add(g.vertex[index]);  //每个元素仅入队一次
        
        while(!queue.isEmpty())
        {
            p = queue.poll();
            for(Vertex q : g.adjacencyMap.get(p))
                if(q.isvisited == false)
                {
                    System.out.print(q.name + " ");
                    q.isvisited = true;
                    queue.add(q);
                }
        }
    }
}

class Vertex
{
    char name;
    boolean isvisited;
    
    public Vertex(char name)
    {
        this.name = name;
        this.isvisited = false;
    }
}

class Graph
{
    Vertex[] vertex;  //顶点数组
    int vexnum;  //顶点数
    HashMap<Vertex, LinkedList<Vertex>> adjacencyMap;  //邻接表
    
    public Graph(int vexnum)
    {
        this.vertex = new Vertex[vexnum];
        for(int i = 0; i < this.vertex.length; i++)
            this.vertex[i] = new Vertex((char)('a' + i));
        this.vexnum = vexnum;
    }
    
    public void createGraph()
    {
        //各点与其邻接点的映射
        this.adjacencyMap = new HashMap<>();
        
        
        //无向图
        //a的邻接点
        /*LinkedList<Vertex> aNeighbors = new LinkedList<>();
        aNeighbors.add(vertex[1]);
        aNeighbors.add(vertex[2]);
        //b的邻接点    
        LinkedList<Vertex> bNeighbors = new LinkedList<>();
        bNeighbors.add(vertex[0]);
        bNeighbors.add(vertex[3]);
        bNeighbors.add(vertex[4]);
        //c的邻接点
        LinkedList<Vertex> cNeighbors = new LinkedList<>();
        cNeighbors.add(vertex[0]);
        cNeighbors.add(vertex[3]);
        //d的邻接点
        LinkedList<Vertex> dNeighbors = new LinkedList<>();
        dNeighbors.add(vertex[1]);
        dNeighbors.add(vertex[2]);
        dNeighbors.add(vertex[4]);
        //e的邻接点
        LinkedList<Vertex> eNeighbors = new LinkedList<>();
        eNeighbors.add(vertex[1]);
        eNeighbors.add(vertex[3]);
        //建立映射
        adjacencyMap.put(vertex[0], aNeighbors);
        adjacencyMap.put(vertex[1], bNeighbors);
        adjacencyMap.put(vertex[2], cNeighbors);
        adjacencyMap.put(vertex[3], dNeighbors);
        adjacencyMap.put(vertex[4], eNeighbors);*/
        
        
        //有向图
        //a的邻接点
        LinkedList<Vertex> aNeighbors = new LinkedList<>();
        aNeighbors.add(vertex[2]);
        //b的邻接点
        LinkedList<Vertex> bNeighbors = new LinkedList<>();
        bNeighbors.add(vertex[0]);
        //c的邻接点
        LinkedList<Vertex> cNeighbors = new LinkedList<>();
        cNeighbors.add(vertex[3]);
        //d的邻接点
        LinkedList<Vertex> dNeighbors = new LinkedList<>();
        dNeighbors.add(vertex[1]);
        dNeighbors.add(vertex[4]);
        //e的邻接点
        LinkedList<Vertex> eNeighbors = new LinkedList<>();
        eNeighbors.add(vertex[1]);
        //建立映射
        adjacencyMap.put(vertex[0], aNeighbors);
        adjacencyMap.put(vertex[1], bNeighbors);
        adjacencyMap.put(vertex[2], cNeighbors);
        adjacencyMap.put(vertex[3], dNeighbors);
        adjacencyMap.put(vertex[4], eNeighbors);
    }
    
    public int locateVex(char name)
    {
        int i;
        for(i = 0; /*i != this.vertex.length && */name != this.vertex[i].name; i++);
        return i;
    }
}