package cn.yanhao.breadthfirstsearch;/**
??* 定義圖類*/public class Graph
?{private final int ?Max_VERTS = 6;?? //圖中頂點的個數(shù)private Vertex vertexList[];??????? //用來存儲頂點的數(shù)組//用鄰接矩陣來存儲邊，數(shù)組元素表示沒有邊界，1表示有邊界private ?int adjMat[][];private int nVerts;???????? //頂點個數(shù)private QueueX queue;?????? //用隊列實現(xiàn)廣度優(yōu)先搜索/*頂點類
????? */class Vertex{public char label;public boolean wasVisited;public Vertex(char label){this.label ?= label;wasVisited = false;
???????? }
???? }
???? Graph(){//頂點數(shù)組長度初始化為20vertexList = new Vertex[Max_VERTS];//初始化20x20矩陣adjMat ?= new int[Max_VERTS][Max_VERTS];nVerts = 0; //初始化頂點個數(shù)為0
???? ????//初始化鄰接矩陣所有元素都為0，即所有頂點沒有邊for (int i = 0; i ?< Max_VERTS; i++) {for (int j = 0; j ?< Max_VERTS; j++) {adjMat[i][j] ?= 0;
???????????? }
???????? }queue = new QueueX();
???? }//將頂點添加到數(shù)組中，是否訪問位置置為wasVisited ?= false(未訪問)public ?void addVertex(char lab){//先添加在加1vertexList[nVerts++] = new Vertex(lab);
???? }//用鄰接矩陣表示邊，是對稱的，兩部分都要賦值public ?void addEdge(int start,int end){adjMat[start][end] ?= 1;adjMat[end][start] ?= 1;
???? }//打印某個頂點表示的值public ?void displayVertex(int v){
???????? System.out.print(vertexList[v].label+"");
???? }//找到與某一頂點鄰接且未被訪問的頂點public ?int getAdjUnvisitedVertex(int v){for (int i = 0; i ?< nVerts; i++) {//v頂點與i頂點相鄰且未被訪問if(adjMat[v][i] ?== 1 && vertexList[i].wasVisited ?== false){return i;
???????????? }
???????? }return -1;
???? }/**
????? * 廣度優(yōu)先搜索* 1、用remove方法檢查棧頂* 2、試圖找到這個頂點還未被訪問的鄰接點* 3、如果沒有找到，該頂點出列* 4、如果找到這樣的頂點，訪問這個頂點，并把它放入隊列中*/public void breadthFirstSearch()
???? {//第一個頂點可訪問vertexList[0].wasVisited ?= true;//打印第一個頂點的值displayVertex(0);//隊列插入第一個元素queue.insert(0);int v2;//如果隊列不為空while(!queue.isEmpty()){int v1 = queue.remove();while ((v2 = ?getAdjUnvisitedVertex(v1)) != -1){vertexList[v2].wasVisited ?= true;
???????????????? displayVertex(v2);queue.insert(v2);
???????????? }
???????? }//搜索完畢，初始化，便于下次搜索for (int i = 0; i ?< nVerts; i++) {vertexList[i].wasVisited ?= false;
???????? }
???? }public static ?void main(String[] args) {
???????? Graph graph = new Graph();
???????? graph.addVertex('A');
???????? graph.addVertex('B');
???????? graph.addVertex('C');
???????? graph.addVertex('D');
???????? graph.addVertex('E');
???????? graph.addEdge(0,1);???? //ABgraph.addEdge(1,2);???? //BCgraph.addEdge(0,3);???? //ADgraph.addEdge(3,4);???? //DESystem.out.println("廣度優(yōu)先搜索算法：");
???????? graph.breadthFirstSearch();
???? }
?}