leetcode medium 记录 51-100

	#	Title	Solution	Acceptance	Difficulty	Frequency
	92	Reverse Linked List II		40.3%	Medium
	93	Restore IP Addresses		37.2%	Medium
	94	Binary Tree Inorder Traversal	easy	65.5%	Medium
	95	Unique Binary Search Trees II	easy	42.1%	Medium
	96	Unique Binary Search Trees	陷入到细节了，再做一次	54.2%	Medium
	98	Validate Binary Search Tree	有点意思	28.6%	Medium
	102	Binary Tree Level Order Traversal	X	56.3%	Medium
	103	Binary Tree Zigzag Level Order Traversal	X	49.8%	Medium
	105	Construct Binary Tree from Preorder and Inorder Traversal	X	51.3%	Medium
	106	Construct Binary Tree from Inorder and Postorder Traversal	为毛我的这么慢？？	49.2%	Medium
	109	Convert Sorted List to Binary Search Tree	易错！	49.8%	Medium
	113	Path Sum II	易错	48.7%	Medium
	114	Flatten Binary Tree to Linked List	代码不好看。逻辑不对？	51.5%	Medium
	116	Populating Next Right Pointers in Each Node	X	48.6%	Medium
	117	Populating Next Right Pointers in Each Node II	X	41.8%	Medium
	120	Triangle	easy	45.5%	Medium
	129	Sum Root to Leaf Numbers	X	50.6%	Medium
	130	Surrounded Regions	这个就不会，我那个为啥是错的。总结为什么会错。	29.2%	Medium	当前的back_track得到的解，被之前的干扰了
	131	Palindrome Partitioning		51.4%	Medium
	133	Clone Graph	和130同样的问题。设定flag的时机。	38.6%	Medium
	134	Gas Station	做出来了但是没太搞懂	41.0%	Medium
	137	Single Number II		53.6%	Medium
	138	Copy List with Random Pointer	easy	39.6%	Medium
	139	Word Break	动态规划  类似找硬币。总结	41.5%	Medium
	142	Linked List Cycle II	X	39.4%	Medium
	143	Reorder List	easy	40.3%	Medium
	144	Binary Tree Preorder Traversal	常练习	57.2%	Medium
	145	Binary Tree Postorder Traversal	有点难度	57.2%	Medium
	146	LRU Cache	居然没做对？？	35.3%	Medium
	147	Insertion Sort List		44.2%	Medium
	148	Sort List		45.9%	Medium
	150	Evaluate Reverse Polish Notation	easy 只是顺序要注意	37.6%	Medium
	151	Reverse Words in a String	X	23.4%	Medium
	152	Maximum Product Subarray		32.6%	Medium
	153	Find Minimum in Rotated Sorted Array		45.9%	Medium
	156	Binary Tree Upside Down		56.1%	Medium
	159	Longest Substring with At Most Two Distinct Characters		50.3%	Medium
	161	One Edit Distance		32.8%	Medium
	162	Find Peak Element		43.8%	Medium
	165	Compare Version Numbers		30.1%	Medium
	166	Fraction to Recurring Decimal		22.2%	Medium
	173	Binary Search Tree Iterator		59.7%	Medium
	177	Nth Highest Salary		33.0%	Medium
	178	Rank Scores		49.4%	Medium
	179	Largest Number		30.5%	Medium
	180	Consecutive Numbers		41.8%	Medium
	184	Department Highest Salary		39.5%	Medium
	186	Reverse Words in a String II		45.1%	Medium
	187	Repeated DNA Sequences		41.3%	Medium
	189	Rotate Array		36.4%	Medium