BreathFirstPaths

賈小強
转载请注明原创出处，谢谢！

package com.lab1.test4;

import com.lab1.test1.LinkedQueue;
import com.lab1.test1.LinkedStack;

public class BreathFirstPaths {
    private boolean[] marked;
    private int[] edgeTo;
    private int s;

    public BreathFirstPaths(Graph graph, int s) {
        marked = new boolean[graph.V()];
        edgeTo = new int[graph.V()];
        this.s = s;
        bfs(graph, s);
    }

    private void bfs(Graph graph, int s) {
        LinkedQueue queue = new LinkedQueue<>();
        queue.enqueue(s);
        marked[s] = true;

        while (!queue.isEmpty()) {
            int v = queue.dequeue();
            for (int w : graph.adj(v)) {
                if (!marked[w]) {
                    edgeTo[w] = v;
                    marked[w] = true;
                    queue.enqueue(w);
                }
            }
        }
    }

    private Iterable pathTo(int v) {
        LinkedStack stack = new LinkedStack<>();
        for (int x = v; x != s; x = edgeTo[x]) {
            stack.push(x);
        }
        stack.push(s);
        return stack;
    }

    private boolean hashPathTo(int v) {
        return marked[v];
    }

    public static void main(String[] args) {
        int[][] edges = { { 0, 5 }, { 2, 4 }, { 2, 3 }, { 1, 2 }, { 0, 1 }, { 3, 4 }, { 3, 5 }, { 0, 2 } };
        Graph graph = new Graph(edges);
        int s = 0;
        BreathFirstPaths bfs = new BreathFirstPaths(graph, s);
        for (int v = 0; v < graph.V(); v++) {
            if (bfs.hashPathTo(v)) {
                System.out.print(s + " to " + v + " : ");
                for (int x : bfs.pathTo(v)) {
                    System.out.print(x + " ");
                }
                System.out.println();
            } else {
                System.out.println(s + " to " + v + "Not Connected");
            }
        }
    }
}

输出

0 to 0 : 0 
0 to 1 : 0 1 
0 to 2 : 0 2 
0 to 3 : 0 2 3 
0 to 4 : 0 2 4 
0 to 5 : 0 5 

Happy learning !!