找出二叉查找树中第n大的值

public class NthNode {

// k refers to the counter. it is a global variable.
static int k = 0;

//get the nth largest value in BST
public void getNthnode(Node root, int n) {

if (root == null) return;
getNthnode(root.rightChild, n);
k++;
if (k == n) {
System.out.print(root.toString());
}
getNthnode(root.leftChild, n);
}

public static void main(String[] args) {
Node a = new Node(8);
Node b = new Node(3);
Node c = new Node(10);
Node d = new Node(1);
Node e = new Node(6);
Node f = new Node(14);
Node g = new Node(4);
Node h = new Node(7);
Node i = new Node(13);

a.leftChild = b;
a.rightChild = c;
b.leftChild = d;
b.rightChild = e;
c.rightChild = f;
e.rightChild = g;
e.rightChild = h;
f.leftChild = i;
//the third largest value in BST
new NthNode().getNthnode(a, 3);
}
}

class Node {
Node leftChild = null;
Node rightChild = null;
int value;

Node(int value) {
this.value = value;
}

public String toString() {
return value + "";
}
}