307 |
Range Sum Query - Mmutable |
Medium |
Segment Tree |
304 |
Range Sum Query 2D - Immutable |
Medium |
DP |
303 |
Range Sum Query - Immutable |
Easy |
DP |
301 |
Remove Invalid Parentheses |
Hard |
|
300 |
Longest Increasing Subsequence |
Medium |
DP |
299 |
Bulls and Cows |
Easy |
Hash Map |
297 |
Serialize and Deserialize Binary Tree |
Hard |
Tree Travsersal |
295 |
Find Median from Data Stream |
Hard |
Heap |
292 |
Nim Game |
Easy |
|
290 |
Word Pattern |
Easy |
Hash |
289 |
Game of Life |
Meduim |
Array |
287 |
Find the Duplicate Number |
Hard |
Two Pointers, Linked list |
284 |
Peeking Iterator |
Medium |
Design |
283 |
Moving Zeros |
Easy |
two pointers |
282 |
Expression Add Operators |
Hard |
DFS, String |
279 |
Perfect Squares |
Medium |
BFS, DP |
278 |
First Bad Version |
Easy |
binary search |
275 |
H-Index II |
Medium |
binary search |
274 |
H-Index |
Medium |
|
273 |
Integer to English Words |
Hard |
String |
268 |
Missing Number |
Medium |
|
264 |
Ugly Number II |
Medium |
|
263 |
Ugly Number |
Easy |
|
260 |
Single Number III |
Medium |
|
258 |
Add Digits |
Easy |
|
257 |
Binary Tree Paths |
Easy |
|
242 |
Valid Anagram |
Easy |
|
241 |
Different Ways to Add Parentheses |
Medium |
|
240 |
Search a 2D Matrix II |
Medium |
|
239 |
Sliding Window Maximum |
Hard |
|
238 |
Product of Array Except Self |
Medium |
|
237 |
Delete Node in a Linked List |
Easy |
|
236 |
Lowest Common Ancestor of a Binary Tree |
Medium |
|
235 |
Lowest Common Ancestor of a Binary Search Tree |
Easy |
|
234 |
Palindrome Linked List |
Easy |
|
233 |
Number of Digit One |
Hard |
|
232 |
Implement Queue using Stacks |
Easy |
|
231 |
Power of Two |
Easy |
|
230 |
Kth Smallest Element in a BST |
Medium |
|
229 |
Majority Element II |
Medium |
|
228 |
Summary Ranges |
Medium |
|
227 |
Basic Calculator II |
Medium |
|
226 |
Invert Binary Tree |
Easy |
|
225 |
Implement Stack using Queues |
Easy |
|
224 |
Basic Calculator |
Hard |
|
223 |
Rectangle Area |
Easy |
|
222 |
Count Complete Tree Nodes |
Medium |
|
221 |
Maximal Square |
Medium |
|
220 |
Contains Duplicate III |
Medium |
|
219 |
Contains Duplicate II |
Easy |
|
218 |
The Skyline Problem |
Hard |
|
217 |
Contains Duplicate |
Easy |
|
216 |
Combination Sum III |
Medium |
|
215 |
Kth Largest Element in an Array |
Medium |
|
214 |
Shortest Palindrome |
Hard |
|
213 |
House Robber II |
Medium |
DP |
212 |
Word Search II |
Hard |
|
211 |
Add and Search Word - Data structure design |
Medium |
|
210 |
Course Schedule II |
Medium |
|
209 |
Minimum Size Subarray Sum |
Medium |
|
208 |
Implement Trie (Prefix Tree) |
Medium |
|
207 |
Course Schedule |
Medium |
|
206 |
Reverse Linked List |
Easy |
|
205 |
Isomorphic Strings |
Easy |
|
204 |
Count Primes |
Easy |
|
203 |
Remove Linked List Elements |
Easy |
|
202 |
Happy Number |
Easy |
|
201 |
Bitwise AND of Numbers Range |
Medium |
|
200 |
Number of Islands |
Medium |
|
199 |
Binary Tree Right Side View |
Medium |
|
198 |
House Robber |
Easy |
|
191 |
Number of 1 Bits |
Easy |
|
190 |
Reverse Bits |
Easy |
|
189 |
Rotate Array |
Easy |
|
188 |
Best Time to Buy and Sell Stock IV |
Hard |
|
187 |
Repeated DNA Sequences |
Medium |
|
179 |
Largest Number |
Medium |
|
174 |
Dungeon Game |
Hard |
|
173 |
Binary Search Tree Iterator |
Medium |
|
172 |
Factorial Trailing Zeroes |
Easy |
|
171 |
Excel Sheet Column Number |
Easy |
|
169 |
Majority Element |
Easy |
|
168 |
Excel Sheet Column Title |
Easy |
|
167 |
Two Sum II - Input array is sorted |
Medium |
|
166 |
Fraction to Recurring Decimal |
Medium |
|
165 |
Compare Version Numbers |
Easy |
|
164 |
Maximum Gap |
Hard |
|
162 |
Find Peak Element |
Medium |
|
160 |
Intersection of Two Linked Lists |
Easy |
|
155 |
Min Stack |
Easy |
|
154 |
Find Minimum in Rotated Sorted Array II |
Hard |
|
153 |
Find Minimum in Rotated Sorted Array |
Medium |
|
152 |
Maximum Product Subarray |
Medium |
|
151 |
Reverse Words in a String |
Medium |
|
150 |
Evaluate Reverse Polish Notation |
Medium |
|
149 |
Max Points on a Line |
Hard |
|
148 |
Sort List |
Medium |
|
147 |
Insertion Sort List |
Medium |
|
146 |
LRU Cache |
Hard |
|
145 |
Binary Tree Postorder Traversal |
Hard |
|
144 |
Binary Tree Preorder Traversal |
Medium |
|
143 |
Reorder List |
Medium |
|
142 |
Linked List Cycle II |
Medium |
|
141 |
Linked List Cycle |
Easy |
|
140 |
Word Break II |
Hard |
|
139 |
Word Break |
Medium |
|
138 |
Copy List with Random Pointer |
Hard |
|
137 |
Single Number II |
Medium |
|
136 |
Single Number |
Easy |
|
135 |
Candy |
Hard |
|
134 |
Gas Station |
Medium |
|
133 |
Clone Graph |
Medium |
|
132 |
Palindrome Partitioning II |
Hard |
|
131 |
Palindrome Partitioning |
Medium |
|
130 |
Surrounded Regions |
Medium |
|
129 |
Sum Root to Leaf Numbers |
Medium |
|
128 |
Longest Consecutive Sequence |
Hard |
|
127 |
Word Ladder |
Medium |
|
126 |
Word Ladder II |
Hard |
|
125 |
Valid Palindrome |
Easy |
|
124 |
Binary Tree Maximum Path Sum |
Hard |
|
123 |
Best Time to Buy and Sell Stock III |
Hard |
|
122 |
Best Time to Buy and Sell Stock II |
Medium |
|
121 |
Best Time to Buy and Sell Stock |
Easy |
|
120 |
Triangle |
Medium |
|
119 |
Pascal's Triangle II |
Easy |
|
118 |
Pascal's Triangle |
Easy |
|
117 |
Populating Next Right Pointers in Each Node II |
Hard |
|
116 |
Populating Next Right Pointers in Each Node |
Medium |
|
115 |
Distinct Subsequences |
Hard |
|
114 |
Flatten Binary Tree to Linked List |
Medium |
|
113 |
Path Sum II |
Medium |
|
112 |
Path Sum |
Easy |
|
111 |
Minimum Depth of Binary Tree |
Easy |
|
110 |
Balanced Binary Tree |
Easy |
|
109 |
Convert Sorted List to Binary Search Tree |
Medium |
|
108 |
Convert Sorted Array to Binary Search Tree |
Medium |
|
107 |
Binary Tree Level Order Traversal II |
Easy |
|
106 |
Construct Binary Tree from Inorder and Postorder Traversal |
Medium |
|
105 |
Construct Binary Tree from Preorder and Inorder Traversal |
Medium |
|
104 |
Maximum Depth of Binary Tree |
Easy |
|
103 |
Binary Tree Zigzag Level Order Traversal |
Medium |
|
102 |
Binary Tree Level Order Traversal |
Easy |
|
101 |
Symmetric Tree |
Easy |
|
100 |
Same Tree |
Easy |
|
99 |
Recover Binary Search Tree |
Hard |
|
98 |
Validate Binary Search Tree |
Medium |
|
97 |
Interleaving String |
Hard |
|
96 |
Unique Binary Search Trees |
Medium |
|
95 |
Unique Binary Search Trees II |
Medium |
|
94 |
Binary Tree Inorder Traversal |
Medium |
|
93 |
Restore IP Addresses |
Medium |
|
92 |
Reverse Linked List II |
Medium |
|
91 |
Decode Ways |
Medium |
|
90 |
Subsets II |
Medium |
|
89 |
Gray Code |
Medium |
|
88 |
Merge Sorted Array |
Easy |
|
87 |
Scramble String |
Hard |
|
86 |
Partition List |
Medium |
|
85 |
Maximal Rectangle |
Hard |
|
84 |
Largest Rectangle in Histogram |
Hard |
|
83 |
Remove Duplicates from Sorted List |
Easy |
|
82 |
Remove Duplicates from Sorted List II |
Medium |
|
81 |
Search in Rotated Sorted Array II |
Medium |
|
80 |
Remove Duplicates from Sorted Array II |
Medium |
|
79 |
Word Search |
Medium |
|
78 |
Subsets |
Medium |
|
77 |
Combinations |
Medium |
|
76 |
Minimum Window Substring |
Hard |
|
75 |
Sort Colors |
Medium |
|
74 |
Search a 2D Matrix |
Medium |
|
73 |
Set Matrix Zeroes |
Medium |
|
72 |
Edit Distance |
Hard |
|
71 |
Simplify Path |
Medium |
|
70 |
Climbing Stairs |
Easy |
|
69 |
Sqrt(x) |
Medium |
|
68 |
Text Justification |
Hard |
|
67 |
Add Binary |
Easy |
|
66 |
Plus One |
Easy |
|
65 |
Valid Number |
Hard |
|
64 |
Minimum Path Sum |
Medium |
|
63 |
Unique Paths II |
Medium |
|
62 |
Unique Paths |
Medium |
|
61 |
Rotate List |
Medium |
|
60 |
Permutation Sequence |
Medium |
|
59 |
Spiral Matrix II |
Medium |
|
58 |
Length of Last Word |
Easy |
|
57 |
Insert Interval |
Hard |
|
56 |
Merge Intervals |
Hard |
|
55 |
Jump Game |
Medium |
|
54 |
Spiral Matrix |
Medium |
|
53 |
Maximum Subarray |
Medium |
|
52 |
N-Queens II |
Hard |
|
51 |
N-Queens |
Hard |
|
50 |
Pow(x, n) |
Medium |
|
49 |
Group Anagrams |
Medium |
|
48 |
Rotate Image |
Medium |
|
47 |
Permutations II |
Medium |
|
46 |
Permutations |
Medium |
|
45 |
Jump Game II |
Hard |
|
44 |
Wildcard Matching |
Hard |
|
43 |
Multiply Strings |
Medium |
|
42 |
Trapping Rain Water |
Hard |
|
41 |
First Missing Positive |
Hard |
|
40 |
Combination Sum II |
Medium |
|
39 |
Combination Sum |
Medium |
|
38 |
Count and Say |
Easy |
|
37 |
Sudoku Solver |
Hard |
|
36 |
Valid Sudoku |
Easy |
|
35 |
Search Insert Position |
Medium |
|
34 |
Search for a Range |
Medium |
|
33 |
Search in Rotated Sorted Array |
Hard |
|
32 |
Longest Valid Parentheses |
Hard |
|
31 |
Next Permutation |
Medium |
|
30 |
Substring with Concatenation of All Words |
Hard |
|
29 |
Divide Two Integers |
Medium |
|
28 |
Implement strStr() |
Easy |
|
27 |
Remove Element |
Easy |
|
26 |
Remove Duplicates from Sorted Array |
Easy |
|
25 |
Reverse Nodes in k-Group |
Hard |
|
24 |
Swap Nodes in Pairs |
Easy |
|
23 |
Merge k Sorted Lists |
Hard |
|
22 |
Generate Parentheses |
Medium |
|
21 |
Merge Two Sorted Lists |
Easy |
|
20 |
Valid Parentheses |
Easy |
|
19 |
Remove Nth Node From End of List |
Easy |
|
18 |
4Sum |
Medium |
|
17 |
Letter Combinations of a Phone Number |
Medium |
|
16 |
3Sum Closest |
Medium |
|
15 |
3Sum |
Medium |
|
14 |
Longest Common Prefix |
Easy |
|
13 |
Roman to Integer |
Easy |
|
12 |
Integer to Roman |
Medium |
|
11 |
Container With Most Water |
Medium |
|
10 |
Regular Expression Matching |
Hard |
|
9 |
Palindrome Number |
Easy |
|
8 |
String to Integer (atoi) |
Easy |
|
7 |
Reverse Integer |
Easy |
|
6 |
ZigZag Conversion |
Easy |
|
5 |
Longest Palindromic Substring |
Medium |
|
4 |
Median of Two Sorted Arrays |
Hard |
|
3 |
Longest Substring Without Repeating Characters |
Medium |
|
2 |
Add Two Numbers |
Medium |
|
1 |
Two Sum |
Easy |
Hash Map |