将节点插入BST

Question

我的将节点插入BST的代码无法正常工作。 当我尝试显示时，它仅显示树的最后两个节点，即，它以某种方式覆盖了树中的节点。 我做错了什么？ 提前致谢！

public Node Insert(int value)
    {
        Node newNode = new Node();
        newNode.data = value;
        newNode.left = null;
        newNode.right = null;

        if(root == null){
            root = newNode;
            return root;
        }
        else{
            while(root != null){
                if(root.data < value){
                    if(root.right != null){
                        root = root.right;
                    }
                    else{
                        root.right = newNode;
                        break;
                    }
                }
                else{
                    if(root.left != null){
                        root = root.left;
                    }
                    else{
                        root.left = newNode;
                        break;
                    }

                }
            }
            return root;
        }

    }
    public void inOrder(){
        inOrder(this.root);
    }
    private void inOrder(Node root){
        if(root != null){
            inOrder(root.left);
            System.out.println(root.data);
            inOrder(root.right);
        }
    }

Answer 1

根指向树的顶部节点。 在您改变其价值的同时。 您必须使用注释变量（例如'n'）。

“ n”的初始值为“ root”。 而在片刻内，您仅使用“ n”。

if(root == null){
        root = newNode;
        return root;
    }
    else{
        Node n = root;
        while(n != null){
        ...
        }
        return root;
        ...

您必须返回'root'，而不是'n'，因为root不会改变。

Answer 2

请参阅代码中的注释。 希望能帮助到你。

public Node Insert(int value)
{
    Node newNode = new Node();
    newNode.data = value;
    newNode.left = null;
    newNode.right = null;

    if(root == null){
        root = newNode;
        return root;
    }
    else{
        while(root != null){
            if(root.data < value){
                if(root.right != null){
                    root = root.right;
                    // root should point to the head of the tree.
                    /* Here you are changing the variable root to point to some other memory location and the reference to the head of the tree is lost. You should store the reference to the head of the tree in a temporary variable to return later  */
                }
                else{
                    root.right = newNode;
                    break;
                }
            }
            else{
                if(root.left != null){
                    root = root.left;
                   //root should point to the head of the tree.
                    /* Here you are changing the variable root to point to some other memory location and the reference to the head of the tree is lost. You should store the reference to the head of the tree in a temporary variable to return later  */
                }
                else{
                    root.left = newNode;
                    break;
                }

            }
        }
        // return temporary variable which points to the head of the tree here
        return root;
    }

}
public void inOrder(){
    inOrder(this.root);
}
private void inOrder(Node root){
    if(root != null){
        inOrder(root.left);
        System.out.println(root.data);
        inOrder(root.right);
    }
}