Number | Title | Difficulty |
408 | Valid Word Abbreviation | Medium |
407 | Trapping Rain Water II | Hard |
406 | Queue Reconstruction by Height | Medium |
405 | Convert a Number to Hexadecimal | Easy |
404 | Sum of Left Leaves | Easy |
403 | Frog Jump | Hard |
402 | Remove K Digits | Medium |
401 | Binary Watch | Easy |
400 | Nth Digit | Medium |
399 | Evaluate Division | Medium |
398 | Random Pick Index | Medium |
397 | Integer Replacement | Medium |
396 | Rotate Function | Medium |
395 | Longest Substring with At Least K Repeating Characters | Medium |
394 | Decode String | Medium |
393 | UTF-8 Validation | Medium |
392 | Is Subsequence | Easy |
391 | Perfect Rectangle | Hard |
390 | Elimination Game | Medium |
389 | Find the Difference | Easy |
388 | Longest Absolute File Path | Medium |
387 | First Unique Character in a String | Easy |
386 | Lexicographical Numbers | Medium |
385 | Mini parser | Medium |
384 | Shuffle An Array | Medium |
383 | Ransom Note | Easy |
382 | Linked List Random Node | Medium |
381 | Insert Delete GetRandom O(1) Duplicate | Hard |
380 | Insert Delete GetRandom O(1) | Medium |
379 | Design Phone Directory | Medium |
378 | Kth Smallest Element in a Sorted Matrix | Medium |
377 | Combination Sum IV | Medium |
376 | Wiggle sequence | Medium |
375 | Guess number higher or lower ii | Medium |
374 | Guess number higher or lower | Easy |
373 | Find K Pairs with Smallest Sums | Medium |
372 | Super Pow | Medium |
371 | Sum of Two Integers | Easy |
370 | Range Addition | Medium |
369 | Plus One Linked List | Medium |
368 | Largest divisible subset | Medium |
367 | Valid Perfect Square | Medium |
366 | Find Leaves of Binary Tree | Medium |
365 | Water and Jug Problem | Medium |
364 | Nested List Weight Sum II | Medium |
363 | Max Sum of Rectangle No Larger Than K | Hard |
362 | Design Hit Counter | Medium |
361 | Bomb Enemy | Medium |
360 | Sort Transformed Array | Medium |
359 | Logger Rate Limiter | Easy |
358 | Rearrage String K distance Apart | Hard |
357 | Count Numbers with Unique Digits | Medium |
356 | Line Reflection | Medium |
355 | Design Twitter | Medium |
354 | Russian Doll Envelopes | Hard |
353 | Design Snake Game | Medium |
352 | Data Stream as Disjoint Intervals | Hard |
351 | Android unlock patterns | Medium |
350 | Intersection of Two Arrays II | Easy |
349 | Intersection of Two Arrays | Easy |
348 | Design tic-tac-toe | Medium |
347 | Top K frequent elements | Medium |
346 | Moving Average from data stream | Easy |
345 | Reverse Vowels of a String | Easy |
344 | Reverse String | Easy |
343 | Integer Break | Medium |
342 | Power of Four | Easy |
341 | Flatten Nested List Iterator | Medium |
340 | Longest Substring with At Most K Distinct Characters | Hard |
339 | Nested List Weight Sum | Easy |
338 | Counting Bits | Medium |
337 | House Robber III | Medium |
336 | Palindrome Pairs | Hard |
335 | Self Crossing | Hard |
334 | Increasing Triplet Subsequence | Medium |
333 | Largest BST subtree | Medium |
332 | Reconstruct Itinerary | Medium |
331 | Verify Preorder Serialization of a Binary Tree | Medium |
330 | Patching Array | Medium |
329 | Longest Increasing Path in a Matrix | Hard |
328 | Odd Even Linked List | Easy |
327 | Count of Range Sum | Hard |
326 | Power of Three | Easy |
325 | Maximum Size Subarray Sum Equals k | Easy |
324 | Wiggle Sort II | Medium |
323 | Number of Connected Components | Medium |
322 | Coin Change | Medium |
321 | Create Maximum Number | Hard |
320 | Generalized Abbreviation | Medium |
319 | Bulb Switcher | Medium |
318 | Maximum Product of Word Lengths | Medium |
317 | Shortest Distance from All Buildings | Hard |
316 | Remove Duplicate Letters | Medium |
315 | Count of Smaller Numbers After Self | Hard |
314 | Binary Tree Vertical Order Traversal | Medium |
313 | Super Ugly Number | Medium |
312 | Burst Balloons | Medium |
311 | Sparse Matrix Multiplication | Medium |
310 | Minimum Height Trees | Medium |
309 | Best Time to Buy and Sell Stock with Cooldown | Medium |
308 | Range Sum Query 2D - Mutable | Hard |
307 | Range Sum Query - Mutable | Medium |
306 | Additive Number | Medium |
305 | Number of Islands II | Hard |
304 | Range Sum Query 2D - Immutable | Medium |
303 | Range Sum Query - Immutable | Easy |
302 | Smallest Rectangle Enclosing Black Pixels | Hard |
301 | Remove Invalid Parentheses | Hard |
300 | Longest Increasing Subsequence | Medium |
299 | Bulls and Cows | Easy |
298 | Binary Tree Longest Consecutive Sequence | Medium |
297 | Serialize and Deserialize Binary Tree | Medium |
296 | Best Meeting Point | Hard |
295 | Find Median from Data Stream | Hard |
294 | Flip Game II | Medium |
293 | Flip Game | Easy |
292 | Nim Game | Easy |
291 | Word Pattern II | Hard |
290 | Word Pattern | Easy |
289 | Game of Life | Medium |
288 | Unique Word Abbreviation | Easy |
287 | Find the Duplicate Number | Hard |
286 | Walls and Gates | Medium |
285 | Inorder Successor in BST | Medium |
284 | Peeking Iterator | Medium |
283 | Moving Zeroes | Easy |
282 | Expression Add Operators | Hard |
281 | Zigzag Iterator | Medium |
280 | Wiggle Sort | Medium |
279 | Perfect Squares | Medium |
278 | First Bad Version | Easy |
277 | Find the Celebrity | Medium |
276 | Paint Fence | Easy |
275 | H Index II | Medium |
274 | H Index | Medium |
273 | Integer to English Words | Medium |
272 | Closest Binary Search Tree Value II | Hard |
271 | Encode and Decode Strings | Medium |
270 | Closest Binary Search Tree Value | Easy |
269 | Alien Dictionary | Hard |
268 | Missing Number | Medium |
267 | Palindrome Permutation II | Medium |
266 | Palindrome Permutation | Easy |
265 | Paint House II | Hard |
264 | Ugly Number II | Medium |
263 | Ugly Number | Easy |
261 | Graph Valid Tree | Medium |
260 | Single Number III | Medium |
259 | 3Sum Smaller | Medium |
258 | Add Digits | Easy |
257 | Binary Tree Paths | Easy |
256 | Paint House | Medium |
255 | Verify Preorder Sequence in Binary Search Tree | Medium |
254 | Factor Combinations | Medium |
253 | Meeting Rooms II | Medium |
252 | Meeting Rooms | Easy |
251 | Flatten 2D Vector | Medium |
250 | Count Univalue Subtrees | Medium |
249 | Group Shifted Strings | Easy |
248 | Strobogrammatic Number III | Hard |
247 | Strobogrammatic Number II | Medium |
246 | Strobogrammatic Number | Easy |
245 | Shortest Word Distance III | Medium |
244 | Shortest Word Distance II | Medium |
243 | Shortest Word Distance | 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 | Medium |
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 | Easy |
227 | Basic Calculator II | Medium |
226 | Invert Binary Tree | Easy |
225 | Implement Stack using Queues | Medium |
224 | Basic Calculator | Medium |
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 |
212 | Word search II | Hard |
211 | Add and Search Word | Medium |
210 | Course schedule II | Medium |
209 | Minimum Size Subarray Sum | Medium |
208 | Implement Trie | Medium |
207 | Course schedule | Medium |
205 | Revese linkedlist | Easy |
205 | Isomorphic Strings | Easy |
204 | Count primes | Medium |
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 |
176 | Reverse Words in a String II | 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 |
166 | Fraction to Recurring Decimal | Medium |
165 | Compare Version Numbers | Easy |
164 | Maximum Gap | Hard |
163 | Missing Ranges | Medium |
162 | Find Peak Element | Medium |
161 | One Edit Distance | Medium |
160 | Intersection of Two Linked Lists | Easy |
159 | Longest Substring with At Most Two Distinct Characters | Hard |
158 | Read N Characters Given Read4 II - Call multiple times | Hard |
157 | Read N Characters Given Read4 | Easy |
156 | Binary Tree Upside Down | Medium |
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 | Medium |
140 | Word Break II | Hard |
139 | Word Break | Medium |
138 | Copy List with Random Pointer | Hard |
137 | Single Number II | Medium |
136 | Single Number | Medium |
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 II | Hard |
126 | Word Ladder | Medium |
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 | Medium |
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 | Medium |
105 | Construct Binary Tree from Preorder and Inorder | 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 II | Medium |
95 | Unique Binary Search Trees | Medium |
94 | Binary Tree Inorder Traversal | Medium |
93 | Restore IP Addresses | Medium |
92 | Reverse linked List II | Medium |
91 | Subsets II | Medium |
90 | Decode Ways | 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 II | Medium |
82 | Remove Duplicates from Sorted List | Easy |
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 | Plus One | Easy |
66 | Valid Number | Easy |
65 | Add Binary | Easy |
64 | Merge Two Sorted Lists | Easy |
63 | Minimum Path Sum | Medium |
62 | Unique Paths II | Medium |
61 | Unique Paths | Medium |
60 | Rotate List | Medium |
59 | Permutation Sequence | Medium |
58 | Spiral Matrix II | Medium |
57 | Length of Last Word | Easy |
56 | Insert Interval | Hard |
55 | Merge Intervals | Hard |
54 | Jump Game | Medium |
53 | Spiral Matrix | Medium |
52 | Maximum Subarray | Medium |
51 | N-Queens II | Hard |
50 | N-Queens | Hard |
49 | “Pow(x, n)” | Medium |
48 | Anagrams | Medium |
47 | Rotate Image | Medium |
46 | Permutations II | Hard |
45 | Permutations | Medium |
44 | Jump Game II | Hard |
43 | Wildcard Matching | Hard |
41 | Trapping Rain Water | Hard |
40 | First Missing Positive | Hard |
39 | Combination Sum II | Medium |
38 | Combination Sum | Medium |
37 | Count and Say | Easy |
36 | Sudoku Solver | Hard |
35 | Valid Sudoku | Easy |
34 | Search Insert Position | Medium |
33 | Search for a Range | Medium |
31 | Longest Valid Parentheses | Hard |
32 | Search in Rotated Sorted Array | Hard |
30 | Next Permutation | Medium |
29 | Substring with Concatenation of All Words | Hard |
28 | Divide Two Integers | Medium |
27 | Implement strStr() | Easy |
26 | Remove Element | Easy |
25 | Remove Duplicates from Sorted Array | Easy |
24 | Reverse Nodes in k-Group | Hard |
23 | Swap Nodes in Pairs | Medium |
22 | Merge k Sorted Lists | Hard |
21 | Generate Parentheses | Medium |
20 | Valid Parentheses | Easy |
19 | Remove Nth Node From End of List | Easy |
18 | Letter Combinations of a Phone Number | Medium |
17 | 4Sum | 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 | Medium |