深度优先搜索之寻找路径

算法思想：数组edgeTo数组记录的值是当前结点，下标为其邻接点（即路径的下一个结点）

public class DepthFirstSearch {    private boolean[] marked;    private int[] edgeTo;//从起点到一个顶点的已知路径上的最后一个点    private final int s;//起点    public DepthFirstSearch(Graphics G,int s){        marked = new boolean[G.v()];        edgeTo = new int[G.v()];        this.s = s;        dfs(G,s);    }    private void dfs(Graphics G, int v) {        marked[v] = true;//标记遍历过的顶点        for(int w:G.adj(v)){            if(!marked[w]){                edgeTo[w] = v;                dfs(G,w);            }        }    }    public boolean hasPath(int v){        return marked[v];       }    public void path(int v,Vector vec){        Stack stack = null;        int p = v;        while(p != s){            stack.push(p);            p = edgeTo[p];        }        vec.clear();        while(!stack.empty()){            vec.add(stack.peek());            stack.pop();        }    }}