1 . two sum
2 . add two numbers
3 . longest substring without repeating characters
4 . median of two sorted arrays
5 . longest palindromic substring
6 . zigzag conversion
7 . reverse integer
8 . string to integer
9 . palindrome number
10 . regular expression matching
11 . container with most water
12 . integer to roman
13 . roman to integer
14 . longest common prefix
15 . 3 sum
16 . 3 sum closest
17 . letter combinations of a phone number
18 . 4 sum
19 . remove nth node from end of list
20 . valid parentheses
21 . merge two sorted lists
22 . generate parentheses
23 . merge k sorted lists
24 . swap nodes in pairs
25 . reverse nodes in k group
26 . remove duplicates from sorted array
27 . remove element
28 . implement strStr()
29 . divide two integers
30 . substring with concatenation of all words
31 . next permutation
32 . longest valid parentheses
33 . search in rotated sorted array(hard?)
34 . search for a range
35 . search insert position
36 . valid Sudoku
37 . Sudoku solver
38 . count and say
39 . combination sum
40 . combination sum II
41 . first missing positive
42 . trapping rain water
43 . multiply strings
44 . wildcard matching
45 . jump game II
46 . permutations
47 . permutations II
48 . rotate image
50 . pow(x, n)
51 . n queens
52 . n queens II
53 . maximum subarray
54 . spiral matrix
55 . jump game
56 . merge intervals
57 . insert interval
58 . length of last word
59 . spiral matrix II
61 . rotate list
62 . unique paths
64 . minimum path sum
65 . valid number
66 . plus one
67 . add binary
69 . sqrt(x)
70 . climbing stairs
73 . set matrix zeroes
74 . search a 2D matrix
78 . subsets
80 . remove duplicates from sorted array II
81 . search in rotated sorted array II
83 . remove duplicates from sorted list
88 . merge sorted array
100 . same tree
104 . maximum depth of binary tree
118 . Pascal's triangle
119 . Pascal's triangle II
120 . triangle
125 . valid palindrome
135 . candy
136 . single number
141 . linked list cycle
144 . binary tree preorder traversal
145 . binary tree postorder traversal
151 . reverse words in a string
155 . min stack
168 . Excel sheet column title
169 . majority element
171 . Excel sheet column number
172 . factorial trailing zeroes
189 . rotate array
190 . reverse bits
191 . number of 1 bits
198 . house robber
202 . happy number
203 . remove linked list elements
204 . count primes
205 . isomorphic strings
206 . reverse linked list
213 . house robber II
217 . contains duplicate
219 . contains duplicate II
221 . maximal square
223 . rectangle area
226 . invert binary tree
231 . power of two
233 . number of digit one
234 . palindrome linked list
237 . delete node in a linked list
239 . sliding window maximum
240 . search a 2D matrix II
242 . valid anagram
257 . binary tree paths
258 . add digits
263 . ugly number
264 . ugly number II
268 . missing number
278 . first bad version
287 . find the duplicate number
283 . move zeroes
290 . word pattern
292 . nim game
295 . find median from data stream
299 . bulls and cows
303 . range sum query
322 . coin change
326 . power of three
328 . odd even linked list
338 . counting bits
342 . power of four
343 . integer break
344 . reverse string
345 . reverse vowels of a string
349 . intersection of two arrays
350 . intersection of two arrays II