902. Kth Smallest Element in a BST
Given a binary search tree, write a function kthSmallest to find the kth smallest element in it.
You may assume k is always valid, 1 ≤ k ≤ BST's total elements.
样例
Given root = {1,2}, k = 2, return 2.
/**
* Definition of TreeNode:
* class TreeNode {
* public:
* int val;
* TreeNode *left, *right;
* TreeNode(int val) {
* this->val = val;
* this->left = this->right = NULL;
* }
* }
*/
class Solution {
public:
/**
* @param root: the given BST
* @param k: the given k
* @return: the kth smallest element in BST
*/
//迭代遍历到最后(思考如何提前终止)
int count = 0;
int res;
int kthSmallest(TreeNode * root, int k) {
// write your code here
if (root->left != NULL) kthSmallest(root->left, k);
if (++count == k) res = root->val; //①
if (root->right != NULL) kthSmallest(root->right, k);
return res;
}
//循环
int kthSmallest(TreeNode * root, int k) {
// write your code here
std::stack<TreeNode*> sta;
while (true) {
while (root) {
sta.push(root);
root = root->left;
}
if (sta.empty()) break;
root = sta.top();
sta.pop();
if(--k==0) return root->val;
root = root->right;
}
}
};
902. Kth Smallest Element in a BST的更多相关文章
- 【LeetCode】230. Kth Smallest Element in a BST (2 solutions)
Kth Smallest Element in a BST Given a binary search tree, write a function kthSmallest to find the k ...
- [leetcode] 230. Kth Smallest Element in a BST 找出二叉搜索树中的第k小的元素
题目大意 https://leetcode.com/problems/kth-smallest-element-in-a-bst/description/ 230. Kth Smallest Elem ...
- LeetCode 230. 二叉搜索树中第K小的元素(Kth Smallest Element in a BST)
230. 二叉搜索树中第K小的元素 230. Kth Smallest Element in a BST 题目描述 给定一个二叉搜索树,编写一个函数 kthSmallest 来查找其中第 k 个最小的 ...
- 【刷题-LeetCode】230. Kth Smallest Element in a BST
Kth Smallest Element in a BST Given a binary search tree, write a function kthSmallest to find the k ...
- [LeetCode] Kth Smallest Element in a BST 二叉搜索树中的第K小的元素
Given a binary search tree, write a function kthSmallest to find the kth smallest element in it. Not ...
- Leetcode Kth Smallest Element in a BST
Given a binary search tree, write a function kthSmallest to find the kth smallest element in it. Not ...
- Leetcode 230. Kth Smallest Element in a BST
Given a binary search tree, write a function kthSmallest to find the kth smallest element in it. Not ...
- Kth Smallest Element in a BST
Given a binary search tree, write a function kthSmallest to find the kth smallest element in it. Not ...
- 230. Kth Smallest Element in a BST ——迭代本质:a=xx1 while some_condition: a=xx2
Given a binary search tree, write a function kthSmallest to find the kth smallest element in it. Not ...
随机推荐
- C - 继续畅通工程 最小生成树
省政府“畅通工程”的目标是使全省任何两个村庄间都可以实现公路交通(但不一定有直接的公路相连,只要能间接通过公路可达即可).现得到城镇道路统计表,表中列出了任意两城镇间修建道路的费用,以及该道路是否已经 ...
- .net 解决伪静态下,html页面无法访问
1.在<system.web>节点下添加: <!--URL重写文件设置开始--> <httpHandlers> <add verb="*" ...
- 配置数据库方言——hibernate
RDBMS 方言 DB2 org.hibernate.dialect.DB2Dialect DB2 AS/400 org.hibernate.dialect.DB2400Dialect DB2 OS3 ...
- UVA215-Spreadsheet Calculator(模拟+拓扑排序)
Problem UVA215-Spreadsheet Calculator Accept:401 Submit:2013 Time Limit: 3000 mSec Problem Descript ...
- Linux:Day6(上) egrep、条件测试
egrep及扩展的正则表达式: egrep = grep -E 扩展正则表达式的元字符: 或者:a | b 练习: 1.显示当前系统root.centos或user1用户的默认shell和UID: 2 ...
- shut immediate 数据库遭遇 ORA-24324 ORA-24323
SQL> shut immediateORA-24324: service handle not initializedORA-24323: value not allowedORA-27140 ...
- selenium:断言
在编写自动化测试脚本时,为了使“机器”去自动辨识test case的执行结果是True还是False,一般都需要在用例执行过程中获取一些信息,来判断用例的执行时成功还是失败. 判断成功失败与否,就涉及 ...
- Python学习总结 13 Scrapy
当前环境是 Win8 64位的,使用的Python 3.5 版本. 一 安装Scrapy 1,安装 lxml pip install lxml -i https://pypi.douban.com/s ...
- LOJ6036 编码 2-SAT、Trie
传送门 每个串只有一个?,?还只能填0或者1,不难想到2-SAT求解. 一个很暴力的想法是枚举?填0或者1,然后对所有可能的前缀连边.这样边数是\(O(n^2)\)的,需要优化. 看到前缀不难想到Tr ...
- Vue-插槽学习
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8&quo ...