Validate Binary Search Tree
LeetCode https://leetcode.cn/problems/validate-binary-search-tree/ /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right;...
LeetCode https://leetcode.cn/problems/validate-binary-search-tree/ /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right;...
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...
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; * ...
LeetCode https://leetcode.cn/problems/diameter-of-binary-tree/ /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * ...
LeetCode https://leetcode.cn/problems/symmetric-tree/ /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeN...
LeetCode https://leetcode.cn/problems/invert-binary-tree/ Recursive /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode righ...
LeetCode https://leetcode.cn/problems/binary-tree-level-order-traversal/ /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode ...
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...
LeetCode https://leetcode.cn/problems/binary-tree-inorder-traversal/ 10 == root / \ 5 15 / \ / \ 2 7 12 20 ...
LeetCode https://leetcode.cn/problems/first-unique-character-in-a-string/ class Solution { public int firstUniqChar(String s) { HashMap<Character, Integer> map = new HashMap<...