原创 Leetcode 78 & 90. Subsets I&II
Subsets I Given a set of distinct integers, nums, return all possible subsets (the power set). Note: The solution s
2020-06-07 17:36:42
原创 Leetcode 94 & 102 & 144 & 145. Binary Tree Traversal (dfs & bfs)
Binart tree traversal: dfs: inorder & preorder & postorder bfs: level 1. dfs Inorder: stack & recursive stack # D
2020-06-07 17:36:32
原创 Leetcode 100 & 101. Same Tree & Symmetric Tree
Same Tree # Definition for a binary tree node. # class TreeNode: # def __init__(self, x): # self.val =
2020-06-07 17:36:32
原创 Leetcode 108. Convert Sorted Array to Binary Search Tree
Given an array where elements are sorted in ascending order, convert it to a height balanced BST. For this problem, a
2019-01-18 19:54:15
原创 Leetcode 103. Binary Tree Zigzag Level Order Traversal
Given a binary tree, return the zigzag level order traversal of its nodes’ values. (ie, from left to right, then righ
2019-01-18 19:54:15
原创 Leetcode 102 & 107. Binary Tree Level Order Traversal I & II
Binary Tree Level Order Traversal Given a binary tree, return the bottom-up level order traversal of its nodes’ val
2019-01-18 19:54:15
原创 Leetcode 105 & 106. Construct Binary Tree from Preorder and Inorder & Inorder and Postorder
Construct Binary Tree from Preorder and Inorder Given preorder and inorder traversal of a tree, construct the binary
2019-01-18 19:54:15
原创 Leetcode 104 & 111. Minimum & Maximum Depth of Binary Tree
Maximum Depth of Binary Tree # Definition for a binary tree node. # class TreeNode: # def __init__(self, x): #
2019-01-07 20:56:49
原创 Leetcode 99. Recover Binary Search Tree
# Definition for a binary tree node. # class TreeNode: # def __init__(self, x): # self.val = x #
2019-01-07 20:56:48
原创 Leetcode 100. Same Tree
# Definition for a binary tree node. # class TreeNode: # def __init__(self, x): # self.val = x #
2019-01-07 20:56:48
原创 Leetcode 95 & 96. Unique Binary Search Trees I & II
Unique Binary Search Trees I Given n, how many structurally unique BST’s (binary search trees) that store values 1 …
2019-01-02 21:09:23
2
原创 Leetcode 98. Validate Binary Search Tree
Same method to inorder traversal # Definition for a binary tree node. # class TreeNode(object): # def __init__(se
2019-01-02 21:09:23
原创 Leetcode 82&83. Remove Duplicates from Sorted List I & II
recursion can be used in II difference between pre=cur(the same node) and pre.val=cur.val (two nodes have the same nu
2018-12-31 21:47:44
原创 Leetcode 86. Partition List
# Definition for singly-linked list. # class ListNode: # def __init__(self, x): # self.val = x #
2018-12-31 21:47:44
原创 Leetcode 88. Merge Sorted Array
class Solution: def merge(self, nums1, m, nums2, n): """ :type nums1: List[int] :type m:
2018-12-31 21:47:44