function Graph (v) {this.vertices = v; //顶点个数this.edges = 0;  //边条数this.adj = [];for(var i = 0; i < this.vertices; ++i) {this.adj[i] = [];  //二维数组//this.adj[i].push("");}this.addEdge = addEdge;this.showGraph = showGraph;
}
function addEdge(v,w) {  //构建边this.adj[v].push(w);this.adj[w].push(v);this.edges++;
}
function showGraph() {var str = "";for(var i = 0; i < this.vertices; ++i) {str = i + "-->";for(var j = 0; j < this.vertices; ++j) {if(this.adj[i][j] != undefined) {str += this.adj[i][j] + " ";}}console.log(str);}
}

function init() {for(var i = 0; i < this.vertices; ++i) {this.adj[i] = [];  this.marked[i] = false;}
}
function dfs(v) {this.marked[v] = true;var adj = this.adj[v],nextAdj;if(adj != undefined) {console.log("Visited vertex: " + v);}for(var w in adj) {var nextAdj = this.adj[v][w];if(!this.marked[nextAdj]) {this.dfs(nextAdj);}}
}

//在 Graph 中添加this.edgeTo = [];来记录哪个顶点访问到它，所以第一个会是undefined;function dfs(s) {var queue = [],adj = this.adj[s],nextAdj;this.marked[s] = true;queue.push(s);while(queue.length > 0) {var v = queue.shift();if(v != undefined) {console.log("Visited vertex: " + v);}adj = this.adj[v];for(var w in adj) {var nextAdj = this.adj[v][w];if(!this.marked[nextAdj]) {this.edgeTo[nextAdj] = v;this.marked[nextAdj] = true;queue.push(nextAdj);}}}
}

function pathTo(s,v) { //from s to v;this.dfs(s);    if(!this.hasPathTo(v)) {return undefined;}var path = [];for(var i = v;i != s; i = this.edgeTo[i]) {path.push(i);}path.push(s);this.printPath(path);
}
function hasPathTo(v) {return this.marked[v];
}
function printPath(paths) {var str = "";while(paths.length > 0) {if(paths.length > 1) {str += paths.pop() + "-";} else {str += paths.pop();}}console.log(str);
}