剑指offer54 二叉搜索树的第K大节点 Java

public class BinaryTreeK54 {
    static class Node {
        int val;
        Node left;
        Node right;

        public Node(int val) {
            this.val = val;
        }

        @Override
        public String toString() {
            return "Node{" +
                    "val=" + val +
                    ", left=" + left +
                    ", right=" + right +
                    '}';
        }
    }

    public static void main(String[] args) {
        Node root = new Node(8);
        Node node21 = new Node(6);
        Node node22 = new Node(10);
        Node node31 = new Node(5);
        Node node32 = new Node(7);
        Node node33 = new Node(9);
        Node node34 = new Node(11);
        root.left = node21;
        root.right = node22;
        node21.left = node31;
        node21.right = node32;
        node22.left = node33;
        node22.right = node34;
        numberK(root, 7);
    }
    static public int count = 0;
    private static void numberK(Node root, int k) {
        if (root == null)
            return;
        numberK(root.left, k);
        {
            count++;
            if (count == k) {
                System.out.println("find it: " + root.val);
                return;
            }
        }
        numberK(root.right, k);
    }
}