题解 | #二叉搜索树的第k个节点（递归中序遍历）#

import java.util.*;

public class Solution {
     int count = 0;
     int result = -1;
    public int KthNode (TreeNode proot, int k) {
        // write code here
        if (proot!=null){
		  // 遍历左子树
            KthNode(proot.left,k);
		  // 处理当前节点
            count++;
            if (count==k)
                result = proot.val;
		  // 遍历右子树
            KthNode(proot.right,k);
        }
        return result;
    }
}