001 | Two Sum | HT | Click Here |
002 | Add Two Numbers | List,Math | Click Here |
003 | Longest Substring Without Repeati… | HT,TP | Click Here |
004 | Median of Two Sorted Arrays | | Click Here |
005 | Longest Palindromic Substring | String ,DP | Click Here |
006 | ZigZag Conversion | | Click Here |
007 | Reverse Integer | Math | Click Here |
008 | String to Integer | Math,String | Click Here |
009 | Palindrome Number | Math | Click Here |
010 | Regular Expression Matching | | Click Here |
011 | Container With Most Water | | Click Here |
012 | Integer to Roman | Math | Click Here |
013 | Roman to Integer | Math | Click Here |
014 | Longest Common Prefix | String | Click Here |
015 | 3Sum | TP | Click Here |
016 | 3Sum Closest | TP,Array | Click Here |
017 | Letter Combinations of a Phone Number | Btr | Click Here |
018 | 4Sum | TP,Array | Click Here |
019 | Remove Nth Node From End of List | List | Click Here |
020 | Valid Parentheses | Stack,String | Click Here |
021 | Merge Two Sorted Lists | List | Click Here |
022 | Generate Parentheses | Backtracking | Click Here |
023 | Merge k Sorted Lists | | Click Here |
024 | Swap Nodes in Pairs | List | Click Here |
025 | Reverse Nodes in k-Group | | Click Here |
026 | Remove Duplicates from Sorted Array | TP,Array | Click Here |
027 | Remove Element | TP | Click Here |
028 | Implement strStr() | KMP,String | Click Here |
029 | Divide Two Integers | | Click Here |
030 | Substring with Concatenation of A… | | Click Here |
031 | Next Permutation | Math | Click Here |
032 | Longest Valid Parentheses | | Click Here |
033 | Search in Rotated Sorted Array | | Click Here |
034 | Search for a Range | BS | Click Here |
035 | Search Insert Position | BS | Click Here |
036 | Valid Sudoku | | Click Here |
037 | Sudoku Solver | | Click Here |
038 | Count and Say | String | Click Here |
039 | Combination Sum | Btr | Click Here |
040 | Combination Sum II | Btr | Click Here |
041 | First Missing Positive | | Click Here |
042 | Trapping Rain Water | | Click Here |
043 | Multiply Strings | Math | Click Here |
044 | Wildcard Matching | | Click Here |
045 | Jump Game II | | Click Here |
046 | Permutations | Backtracking | Click Here |
047 | Permutations II | Btr | Click Here |
048 | Rotate Image | Array | Click Here |
049 | Anagrams | HT,String | Click Here |
050 | Pow(x, n) | Math,BS | Click Here |
051 | N-Queens | | Click Here |
052 | N-Queens II | Btr | Click Here |
053 | Maximum Subarray | DP | Click Here |
054 | Spiral Matrix | Array | Click Here |
055 | Jump Game | Greedy | Click Here |
056 | Merge Intervals | | Click Here |
057 | Insert Interval | | Click Here |
058 | Length of Last Word | String | Click Here |
059 | Spiral Matrix II | Array | Click Here |
060 | Permutation Sequence | DFS,Math | Click Here |
061 | Rotate List | List | Click Here |
062 | Unique Paths | DP | Click Here |
063 | Unique Paths II | DP | Click Here |
064 | Minimum Path Sum | DP | Click Here |
065 | Valid Number | | Click Here |
066 | Plus One | Math | Click Here |
067 | Add Binary | Math,String | Click Here |
068 | Text Justification | | Click Here |
069 | Sqrt(x) | Math | Click Here |
070 | Climbing Stairs | DP | Click Here |
071 | Simplify Path | | Click Here |
072 | Edit Distance | | Click Here |
073 | Set Matrix Zeroes | Array | Click Here |
074 | Search a 2D Matrix | BS | Click Here |
075 | Sort Colors | TP,Sort | Click Here |
076 | Minimum Window Substring | | Click Here |
077 | Combinations | Btr | Click Here |
078 | Subsets | Btr | Click Here |
079 | Word Search | | Click Here |
080 | Remove Duplicates from Sorted Array II | TP,Array | Click Here |
081 | Search in Rotated Sorted Array II | | Click Here |
082 | Remove Duplicates from Sorted List II | | Click Here |
083 | Remove Duplicates from Sorted List | List | Click Here |
084 | Largest Rectangle in Histogram | | Click Here |
085 | Maximal Rectangle | | Click Here |
086 | Partition List | List,TP | Click Here |
087 | Scramble String | | Click Here |
088 | Merge Sorted Array | TP | Click Here |
089 | Gray Code | Btr,Math | Click Here |
090 | Subsets II | Btr | Click Here |
091 | Decode Ways | | Click Here |
092 | Reverse Linked List II | | Click Here |
093 | Restore IP Addresses | | Click Here |
094 | Binary Tree Inorder Traversal | Binary Tree | Click Here |
096 | Unique Binary Search Trees | DP | Click Here |
095 | Unique Binary Search Trees II | | Click Here |
097 | Interleaving String | | Click Here |
098 | Validate Binary Search Tree | | Click Here |
099 | Recover Binary Search Tree | | Click Here |
100 | Same Tree | DFS,Tree | Click Here |
101 | Symmetric Tree | DFS,Tree | Click Here |
102 | Binary Tree Level Order Traversal | BFS,Tree | Click Here |
103 | Binary Tree Zigzag Level Order Traversal | BFS,Tree | Click Here |
104 | Maximum Depth of Binary Tree | DFS,Tree | Click Here |
105 | Construct Binary Tree from Preord… | Tree | Click Here |
106 | Construct Binary Tree from Inorde… | Tree | Click Here |
107 | Binary Tree Level Order Traversal II | BFS,Tree | Click Here |
108 | Convert Sorted Array to Binary Se… | Tree ,BFS | Click Here |
109 | Convert Sorted List to Binary Sea… | Tree,List | Click Here |
110 | Balanced Binary Tree | DFS | Click Here |
111 | Minimum Depth of Binary Tree | DFS,Tree | Click Here |
112 | Path Sum | DFS,Tree | Click Here |
113 | Path Sum II | DFS,Tree | Click Here |
114 | Flatten Binary Tree to Linked List | DFS,Tree | Click Here |
115 | Distinct Subsequences | | Click Here |
116 | Populating Next Right Pointers in… | Tree ,BFS,DFS | Click Here |
117 | Populating Next Right Pointers in… | Tree,BFS,DFS | Click Here |
118 | Pascals Triangle | Array,Math | Click Here |
119 | Pascal’s Triangle II | Array,Math | Click Here |
120 | Triangle | DP | Click Here |
121 | Best Time to Buy and Sell Stock | DP | Click Here |
122 | Best Time to Buy and Sell Stock II | DP | Click Here |
123 | Best Time to Buy and Sell Stock III | DP | Click Here |
124 | Binary Tree Maximum Path Sum | | Click Here |
125 | Valid Palindrome | TP,String | Click Here |
126 | Word Ladder | | Click Here |
127 | Word Ladder II | | Click Here |
128 | Longest Consecutive Sequence | | Click Here |
129 | Sum Root to Leaf Numbers | Tree,DFS | Click Here |
130 | Surrounded Regions | BFS,Union | Click Here |
131 | Palindrome Partitioning | | Click Here |
132 | Palindrome Partitioning II | | Click Here |
133 | Clone Graph | Graph,DFS,BFS | Click Here |
134 | Gas Station | | Click Here |
135 | Candy | | Click Here |
136 | Single Number | HS,Bit | Click Here |
137 | Single Number II | HS,Bit | Click Here |
138 | Copy List with Random Pointer | | Click Here |
139 | Word Break | | Click Here |
140 | Word Break II | | Click Here |
141 | Linked List Cycle | Linked List | Click Here |
142 | Linked List Cycle II | Linked List | Click Here |
143 | Reorder List | | Click Here |
144 | Binary Tree Preorder Traversal | Binary Tree | Click Here |
145 | Binary Tree Postorder Traversal | Binary Tree | Click Here |
146 | LRU Cache | | Click Here |
147 | Insertion Sort List | | Click Here |
148 | Sort List | List | Click Here |
149 | Max Points on a Line | | Click Here |
150 | Evaluate Reverse Polish Notation | | Click Here |
151 | Reverse Words in a String | String | Click Here |
152 | Maximum Product Subarray | DP | Click Here |
153 | Find Minimum in Rotated Sorted Array | | Click Here |
154 | Find Minimum in Rotated Sorted Array II | | Click Here |
155 | Min Stack | | Click Here |
156 | Binary Tree Upside Down $ | | Not Buy |
157 | Read N Characters Given Read4 $ | | Not Buy |
158 | Read N Characters Given Read4 II … $ | | Not Buy |
159 | Longest Substring with At Most Tw… $ | | Not Buy |
160 | Intersection of Two Linked Lists | List | Click Here |
161 | One Edit Distance $ | Not Buy | Not Buy |
162 | Find Peak Element | BS | Click Here |
163 | Missing Ranges $ | | Not Buy |
164 | Maximum Gap | | Click Here |
165 | Compare Version Numbers | | Click Here |
166 | Fraction to Recurring Decimal | | Click Here |
167 | Two Sum II – Input array is sorted $ | Not Buy | Not Buy |
168 | Excel Sheet Column Title | Math | Click Here |
169 | Majority Element | Math,Bit | Click Here |
170 | Two Sum III – Data structure design $ | | Not Buy |
171 | Excel Sheet Column Number | Math | Click Here |
172 | Factorial Trailing Zeroes | | Click Here |
173 | Binary Search Tree Iterator | Tree | Click Here |
174 | Dungeon Game | | Click Here |
175 | Combine Two Tables | | Click Here |
176 | Second Highest Salary | | Click Here |
177 | Nth Highest Salary | | Click Here |
178 | Rank Scores | | Click Here |
179 | Largest Number | Sort,String | Click Here |
180 | Consecutive Numbers | | Click Here |
181 | Employees Earning More Than Their… | | Click Here |
182 | Duplicate Emails | | Click Here |
183 | Customers Who Never Order | | Click Here |
184 | Department Highest Salary | | Click Here |
185 | Department Top Three Salaries | | Click Here |
186 | Reverse Words in a String II $ | | Not Buy |
187 | Repeated DNA Sequences | | Click Here |
188 | Best Time to Buy and Sell Stock IV | DP | Click Here |
189 | Rotate Array | Array | Click Here |
190 | Reverse Bits | Bit | Click Here |
191 | Number of 1 Bits | Bit | Click Here |
192 | Word Frequency | | Click Here |
193 | Valid Phone Numbers | | Click Here |
194 | Transpose File | | Click Here |
195 | Tenth Line | | Click Here |
196 | Delete Duplicate Emails | | Click Here |
197 | Rising Temperature | | Click Here |
198 | House Robber | DP | Click Here |
199 | Binary Tree Right Side View | Tree,BFS | Click Here |
200 | Number of Islands | DFS,Union | Click Here |
201 | Bitwise AND of Numbers Range | Bit | Click Here |
202 | Happy Number | Hash | Click Here |
203 | Remove Linked List Elements | List | Click Here |
204 | Count Primes | Math | Click Here |
205 | Isomorphic Strings | Hash Table | Click Here |
206 | Reverse Linked List | List | Click Here |
207 | Course Schedule | | Click Here |
208 | Implement Trie (Prefix Tree) | | Click Here |
209 | Minimum Size Subarray Sum | TP,BS | Click Here |
210 | Course Schedule II | | Click Here |
211 | Add and Search Word – Data struct… | | Click Here |
212 | Word Search II | | Click Here |
213 | House Robber II | DP | Click Here |
214 | Shortest Palindrome | | Click Here |
215 | Kth Largest Element in an Array | Heap, Quick Sort | Click Here |
216 | Combination Sum III | Btr | Click Here |
217 | Contains Duplicate | Hash | Click Here |
218 | The Skyline Problem | | Click Here |
219 | Contains Duplicate II | Hash | Click Here |
220 | Contains Duplicate III | | Click Here |
221 | Maximal Square | | Click Here |
222 | Count Complete Tree Nodes | | Click Here |
223 | Rectangle Area | Math | Click Here |
224 | Basic Calculator | | Click Here |
225 | Implement Stack using Queues | Stack,Queue | Click Here |
226 | Invert Binary Tree | Tree | Click Here |
227 | Basic Calculator II | | Click Here |
228 | Summary Ranges | Two Points | Click Here |
229 | Majority Element II | | Click Here |
230 | Kth Smallest Element in a BST | Tree | Click Here |
231 | Power of Two | Bit,Math | Click Here |
232 | Implement Queue using Stacks | Queue,Stack | Click Here |
233 | Number of Digit One | | Click Here |
234 | Palindrome Linked List | List | Click Here |
235 | Lowest Common Ancestor of a Binar… | Tree | Click Here |
236 | Lowest Common Ancestor of a Binary Tree | Tree | Click Here |
237 | Delete Node in a Linked List | List | Click Here |
238 | Product of Array Except Self | Math | Click Here |
239 | Sliding Window Maximum | | Click Here |
240 | Search a 2D Matrix II | BS | Click Here |
241 | Different Ways to Add Parentheses | Divide | Click Here |
242 | Valid Anagram | Hash,Sort | Click Here |
243 | Shortest Word Distance | | Not Buy |
244 | Shortest Word Distance II | | Not Buy |
245 | Shortest Word Distance III | | Not Buy |
246 | Strobogrammatic Number | | Not Buy |
247 | Strobogrammatic Number II | | Not Buy |
248 | Strobogrammatic Number III | | Not Buy |
249 | Group Shifted Strings | | Not Buy |
250 | Count Univalue Subtrees | | Not Buy |
251 | Flatten 2D Vector | | Not Buy |
252 | Meeting Rooms | | Not Buy |
253 | Meeting Rooms II | | Not Buy |
254 | Factor Combinations | | Not Buy |
255 | Verify Preorder Sequence in Binary Search Tree | | Not Buy |
256 | Paint House | | Click Here |
257 | Binary Tree Paths | DFS,Tree | Click Here |
258 | Add Digits | Math | Click Here |
259 | 3Sum Smaller | | Click Here |
260 | Single Number III | Hash,Bit | Click Here |
261 | Graph Valid Tree | | Click Here |
262 | NULL | NULL | NULL |
263 | Ugly Number | Math | Click Here |
264 | Ugly Number II | DP,Heap,Math | Click Here |
266 | Palindrome Permutation | | Click Here |
267 | Palindrome Permutation II | | Click Here |
268 | Missing Number | Math,Bit | Click Here |
269 | Alien Dictionary | | Click Here |
270 | Closest Binary Search Tree Value | | Click Here |
271 | Encode and Decode Strings | | Click Here |
272 | Closest Binary Search Tree Value II | | Click Here |
273 | Integer to English Words | | Click Here |
274 | H-Index | Array | Click Here |
275 | H-Index II | BS | Click Here |
276 | Paint Fence | | Click Here |
277 | Find the Celebrity | | Click Here |
278 | First Bad Version | BS | Click Here |
279 | Perfect Squares | | Click Here |
280 | Wiggle Sort | | Click Here |
281 | Zigzag Iterator | | Click Here |
282 | Expression Add Operators | | Click Here |
283 | Move Zeroes | TP | Click Here |
284 | Peeking Iterator | | Click Here |
285 | Inorder Successor in BST | | Click Here |
286 | Walls and Gates | | Click Here |
287 | Find the Duplicate Number | TP,BS | Click Here |
288 | Unique Word Abbreviation | | Click Here |
289 | Game of Life | | Click Here |
290 | Word Pattern | Hash | Click Here |
291 | Word Pattern II | | Not Buy |
292 | Nim Game | | Click Here |
293 | Flip Game | | Click Here |
294 | Flip Game II | | Click Here |
295 | Find Median from Data Stream | | Click Here |
296 | Best Meeting Point | | Click Here |
297 | Serialize and Deserialize Binary Tree | | Click Here |
298 | Binary Tree Longest Consecutive Sequence | | Click Here |
299 | Bulls and Cows | | Click Here |
300 | Longest Increasing Subsequence | | Click Here |
301 | Remove Invalid Parentheses | | Click Here |
302 | Smallest Rectangle Enclosing Black Pixels | | Click Here |
303 | Range Sum Query – Immutable | DP | Click Here |
304 | Range Sum Query 2D – Immutable | | Click Here |
305 | Number of Islands II | | Click Here |
306 | Additive Number | | Click Here |
307 | Range Sum Query – Mutable | | Click Here |
308 | Range Sum Query 2D – Mutable | | Click Here |
309 | Best Time to Buy and Sell Stock…. | | Click Here |
310 | Minimum Height Trees | | Click Here |
311 | Sparse Matrix Multiplication | | Click Here |
312 | Burst Balloons | Math | Click Here |
313 | Super Ugly Number | DP,Heap | Click Here |
314 | Binary Tree Vertical Order Traversal | | Click Here |
315 | Count of Smaller Numbers After Self | | Click Here |
316 | Remove Duplicate Letters | | Click Here |
317 | Shortest Distance from All Buildings | | Click Here |
318 | Maximum Product of Word Lengths | String,Bit | Click Here |
319 | Bulb Switcher | Math | Click Here |
320 | Generalized Abbreviation | | Click Here |
321 | Create Maximum Number | | Click Here |
322 | Coin Change | | Click Here |
323 | Number of Connected Components… | | Click Here |
324 | Wiggle Sort II | | Click Here |
325 | Maximum Size Subarray Sum Equals k | | Not Buy |
326 | Power of Three | Math | Click Here |
327 | Count of Range Sum | Divide | Click Here |
328 | Odd Even Linked List | List | Click Here |
329 | Longest Increasing Path in a Matrix | | Click Here |
330 | Patching Array | | Click Here |
331 | Verify Preorder Serialization of a BTree | | Click Here |
332 | Reconstruct Itinerary | | Click Here |
333 | Largest BST Subtree | | Click Here |
334 | Increasing Triplet Subsequence | Array,DP | Click Here |
335 | Self Crossing | | Click Here |
336 | Palindrome Pairs | | Click Here |
337 | House Robber III | | Click Here |
338 | Counting Bits | DP,Bit | Click Here |
339 | Nested List Weight Sum | | Click Here |
340 | Longest Substring with At Most K Distinct Characters | | Click Here |
341 | Flatten Nested List Iterator | | Click Here |
342 | Power of Four | Math | Click Here |
343 | Integer Break | Math | Click Here |
344 | Reverse String | String | Click Here |
345 | Reverse Vowels of a String | String,TP | Click Here |
346 | Moving Average from Data Stream | Not Buy | Not Buy |
347 | Top K Frequent Elements | Hash,Heap | Click Here |
348 | Design Tic-Tac-Toe | Not Buy | Not Buy |
349 | Intersection of Two Arrays | Hash,BS, | Click Here |
350 | Intersection of Two Arrays II | TP,Hash | Click Here |