java - 使用 Java 进行 DFS 回溯

Question

我在邻接矩阵中遇到 DFS 回溯问题。这是我的代码:(我将测试添加到主要以防有人想测试它)

public class Graph {

    private int numVertex;
    private int numEdges;
    private boolean[][] adj;

    public Graph(int numVertex, int numEdges) {
        this.numVertex = numVertex;
        this.numEdges = numEdges;
        this.adj = new boolean[numVertex][numVertex];
    }

    public void addEdge(int start, int end){
        adj[start-1][end-1] = true;
        adj[end-1][start-1] = true;
    }

    List<Integer> visited = new ArrayList<Integer>();

    public Integer DFS(Graph G, int startVertex){
        int i=0;

        if(pilha.isEmpty())
            pilha.push(startVertex);

        for(i=1; i<G.numVertex; i++){
            pilha.push(i);
            if(G.adj[i-1][startVertex-1] != false){
                G.adj[i-1][startVertex-1] = false;
                G.adj[startVertex-1][i-1] = false;
                DFS(G,i);
                break;
            }else{
                visited.add(pilha.pop());
            }
            System.out.println("Stack: " + pilha);
        }
        return -1;
    }

    Stack<Integer> pilha = new Stack();

    public static void main(String[] args) {

        Graph g = new Graph(6, 9);

        g.addEdge(1, 2);
        g.addEdge(1, 5);
        g.addEdge(2, 4);
        g.addEdge(2, 5);
        g.addEdge(2, 6);
        g.addEdge(3, 4);
        g.addEdge(3, 5);
        g.addEdge(4, 5);
        g.addEdge(6, 4);

        g.DFS(g, 1);    

    }
}

我正在尝试解决欧拉路径问题。该程序解决了基本图形，但当它需要回溯时，它就是不这样做。我认为问题可能出在堆栈操作或递归 dfs 调用中。我已经尝试了很多东西，但似乎仍然无法弄清楚为什么它不回溯。有人可以帮助我吗？

Answer 1

我只用一个测试过，所以不要相信我的代码。

public class Graph {
    private int numVertex;
    private boolean[][] adj;

    public Graph(int numVertex, int numEdges) {
        this.numVertex = numVertex;
        this.adj = new boolean[numVertex][numVertex];
    }

    public void addEdge(int start, int end){
        adj[start-1][end-1] = true;
        adj[end-1][start-1] = true;
    }

    List<Integer> visited = new ArrayList<Integer>();
    public void DFS(Graph G, int startVertex){
        int i=0;
        pilha.push(startVertex);

        while (!pilha.empty()) {
            int v = pilha.peek();
            Boolean hasNeighbor = false;
            for (i = 1; i <= G.numVertex; i++) {
                if(G.adj[i-1][v-1] != false) {
                    hasNeighbor = true;
                    pilha.push(i);
                    G.adj[i-1][v-1] = false;
                    G.adj[v-1][i-1] = false;
                    break;
                }
            }
            if (!hasNeighbor) {
                visited.add(0, pilha.pop());
            }
        }
        System.out.println("Path: " + visited);
    }

    Stack<Integer> pilha = new Stack<Integer>();

    public static void main(String[] args) {
        Graph g = new Graph(6, 9);
        g.addEdge(1, 2);
        g.addEdge(2, 3);
        g.addEdge(3, 4);
        g.addEdge(4, 5);
        g.addEdge(5, 6);
        g.addEdge(6, 4);
        g.addEdge(4, 2);
        g.addEdge(2, 1);
        g.DFS(g, 1);    
    }
}

此外，与其在尝试解决同一个问题时多次发布同一个问题，不如编辑同一个问题。