java - 二叉树的节点类。出现堆栈溢出错误

Question

我在树数据结构的节点类中收到 Stackoverflow 错误。我知道原因，但我似乎无法解决它。

public class Node {
    Node right;
    Node left;
    String element;
    Node parent;

    public Node(){  
        right = new Node();
        left = new Node();
    }
}

因为我在构造函数中构造新节点，所以出现堆栈溢出。如何构造我的构造函数并避免此错误？

Answer 1

您可以在节点实际存在时按需创建它们。

public class Node {
    Node left, right; // created as required
    String element;
    Node parent;

    public Node(Node parent, String element) {
        this.parent = parent;  
        this.element = element; // if you don't have an element you don't need a Node.
    }
}

注意:您很可能不需要 parent 字段，大多数实现不使用它。

public class Node {
    Node left, right; // created as required
    String element;

    public Node(String element) {
        this.element = element; // if you don't have an element you don't need a Node.
    }

    public void setLeft(Node left) { this.left = left; }
    public void setRight(Node right) { this.right = right; }
}

例如

 Node d = new Node("d");
 d.setLeft(new Node("a"));
 d.setRight(new Node("z"));