Question

我试图提高我对学习实现算法的把握，所以我开始尝试在java中实现深度优先搜索。但是，我无法找到创建Node类并使用它创建树结构的正确方法。你能帮我找一个更好的方法吗？

节点类

public class Node<T>{
T data;
Node<T> parent;
ArrayList<Node<T>> children;

public Node(T data)
{
    this.data = data;
    this.children = new ArrayList<Node<T>>();
}

public Node<T> addChild(T child)
{
    Node<T> childNode = new Node<T>(child);
    childNode.parent = this;
    this.children.add(childNode);
    return childNode;
}

public ArrayList<Node<T>> removeChild(T child)
{
    Node<T> childNode = new Node<T>(child);
    ArrayList<Node<T>> children = this.children;
    children.remove(child);
    return children;
}
}

DepthFirstSearchClass

public class DepthFirstSearch<T>{
public Node<T> root;
public Node<T> goal;
public Hashtable<Node<T>, Boolean> visited;

public boolean DepthFirstSearch(Node<T> root, Node<T> goal)
{
    this.root = root;
    this.goal = goal;

    if(this.root == this.goal)
    {
        System.out.println("The goal has been reached.");
        return true;

    } else {
        if(root.children.size()-1 >0)
        {
            for(Node<T>child: root.children)
            {
                DepthFirstSearch(child, goal);
            }
        }

        return false;
    }
}
}

主要

public class Main{

public static Node<String> rootNode;
public static Node<String> childOne;
public static Node<String> childTwo;
public static Node<String> childThree;
public static DepthFirstSearch dfs;

public static void main(String [] args)
{
    //initializing variables
    rootNode = new Node<String>("rootNode");
    childOne = new Node<String>("childOne");
    childTwo = new Node<String>("childTwo");
    childThree = new Node<String>("childThree");
    dfs = new DepthFirstSearch();

    //building the trees
    rootNode.addChild(childOne);
    rootNode.addChild(childThree);
    childOne.addChild(childTwo);

    dfs.DepthFirstSearch(rootNode, childTwo);

}
}

Answer 1

从代码中删除以下行： if(root.children.size()-1 >0)。

首先，如果给定节点没有子节点，则阻止访问单个子节点，其次for(Node<T>child: root.children)将跳过迭代。

除此之外，你的DFS看起来不错。

问题在java中实现DFS

1 个答案: