Kth Smallest Element in a BST
LeetCode https://leetcode.cn/problems/kth-smallest-element-in-a-bst/ /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode righ...
All too well
Convert Sorted Array to Binary Search Tree
LeetCode https://leetcode.cn/problems/convert-sorted-array-to-binary-search-tree/ /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * ...
Diameter of Binary Tree
LeetCode https://leetcode.cn/problems/diameter-of-binary-tree/ /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * ...
Symmetric Tree
LeetCode https://leetcode.cn/problems/symmetric-tree/ /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeN...
Invert Binary Tree
LeetCode https://leetcode.cn/problems/invert-binary-tree/ Recursive /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode righ...
Binary Tree Level Order Traversal
LeetCode https://leetcode.cn/problems/binary-tree-level-order-traversal/ /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode ...
Maximum Depth of Binary Tree
LeetCode https://leetcode.cn/problems/maximum-depth-of-binary-tree/ /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right...
Binary Tree Inorder Traversal
LeetCode https://leetcode.cn/problems/binary-tree-inorder-traversal/ 10 == root / \ 5 15 / \ / \ 2 7 12 20 ...
First Unique Character in a String
LeetCode https://leetcode.cn/problems/first-unique-character-in-a-string/ class Solution { public int firstUniqChar(String s) { HashMap<Character, Integer> map = new HashMap<...
LRU Cache
LeetCode https://leetcode.cn/problems/lru-cache/ 这是个啥玩意？？ https://en.wikipedia.org/wiki/Cache_replacement_policies#LRU 题目描述 请你设计并实现一个满足LRU (最近最少使用) 缓存 约束的数据结构。 实现 LRUCache 类： LRUCache(int c...