K-th node binary search tree: to prove safety Offer sixty-two

Casual working

Given a binary search tree, please find the first k smaller nodes therein. For example, (5,3,7,2,4,6,8), the numerical values ​​according to the third junction point is 4 summary.


Binary search tree? Not that it ordered in order to find out the first of several small, it can be positioned directly in the order sequence.


public class Solution {
     int index = 0; //计数器
    TreeNode KthNode(TreeNode root, int k)
        if(root != null){ //中序遍历寻找第k个
            TreeNode node = KthNode(root.left,k);
            if(node != null)
                return node;
            index ++;
            if(index == k)
                return root;
            node = KthNode(root.right,k);
            if(node != null)
                return node;
        return null;

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Origin blog.csdn.net/weixin_44015043/article/details/105422808