├── LICENSE └── README.md /LICENSE: -------------------------------------------------------------------------------- 1 | Mozilla Public License Version 2.0 2 | ================================== 3 | 4 | 1. Definitions 5 | -------------- 6 | 7 | 1.1. "Contributor" 8 | means each individual or legal entity that creates, contributes to 9 | the creation of, or owns Covered Software. 10 | 11 | 1.2. "Contributor Version" 12 | means the combination of the Contributions of others (if any) used 13 | by a Contributor and that particular Contributor's Contribution. 14 | 15 | 1.3. "Contribution" 16 | means Covered Software of a particular Contributor. 17 | 18 | 1.4. "Covered Software" 19 | means Source Code Form to which the initial Contributor has attached 20 | the notice in Exhibit A, the Executable Form of such Source Code 21 | Form, and Modifications of such Source Code Form, in each case 22 | including portions thereof. 23 | 24 | 1.5. "Incompatible With Secondary Licenses" 25 | means 26 | 27 | (a) that the initial Contributor has attached the notice described 28 | in Exhibit B to the Covered Software; or 29 | 30 | (b) that the Covered Software was made available under the terms of 31 | version 1.1 or earlier of the License, but not also under the 32 | terms of a Secondary License. 33 | 34 | 1.6. "Executable Form" 35 | means any form of the work other than Source Code Form. 36 | 37 | 1.7. "Larger Work" 38 | means a work that combines Covered Software with other material, in 39 | a separate file or files, that is not Covered Software. 40 | 41 | 1.8. "License" 42 | means this document. 43 | 44 | 1.9. "Licensable" 45 | means having the right to grant, to the maximum extent possible, 46 | whether at the time of the initial grant or subsequently, any and 47 | all of the rights conveyed by this License. 48 | 49 | 1.10. "Modifications" 50 | means any of the following: 51 | 52 | (a) any file in Source Code Form that results from an addition to, 53 | deletion from, or modification of the contents of Covered 54 | Software; or 55 | 56 | (b) any new file in Source Code Form that contains any Covered 57 | Software. 58 | 59 | 1.11. "Patent Claims" of a Contributor 60 | means any patent claim(s), including without limitation, method, 61 | process, and apparatus claims, in any patent Licensable by such 62 | Contributor that would be infringed, but for the grant of the 63 | License, by the making, using, selling, offering for sale, having 64 | made, import, or transfer of either its Contributions or its 65 | Contributor Version. 66 | 67 | 1.12. "Secondary License" 68 | means either the GNU General Public License, Version 2.0, the GNU 69 | Lesser General Public License, Version 2.1, the GNU Affero General 70 | Public License, Version 3.0, or any later versions of those 71 | licenses. 72 | 73 | 1.13. "Source Code Form" 74 | means the form of the work preferred for making modifications. 75 | 76 | 1.14. "You" (or "Your") 77 | means an individual or a legal entity exercising rights under this 78 | License. For legal entities, "You" includes any entity that 79 | controls, is controlled by, or is under common control with You. For 80 | purposes of this definition, "control" means (a) the power, direct 81 | or indirect, to cause the direction or management of such entity, 82 | whether by contract or otherwise, or (b) ownership of more than 83 | fifty percent (50%) of the outstanding shares or beneficial 84 | ownership of such entity. 85 | 86 | 2. License Grants and Conditions 87 | -------------------------------- 88 | 89 | 2.1. Grants 90 | 91 | Each Contributor hereby grants You a world-wide, royalty-free, 92 | non-exclusive license: 93 | 94 | (a) under intellectual property rights (other than patent or trademark) 95 | Licensable by such Contributor to use, reproduce, make available, 96 | modify, display, perform, distribute, and otherwise exploit its 97 | Contributions, either on an unmodified basis, with Modifications, or 98 | as part of a Larger Work; and 99 | 100 | (b) under Patent Claims of such Contributor to make, use, sell, offer 101 | for sale, have made, import, and otherwise transfer either its 102 | Contributions or its Contributor Version. 103 | 104 | 2.2. Effective Date 105 | 106 | The licenses granted in Section 2.1 with respect to any Contribution 107 | become effective for each Contribution on the date the Contributor first 108 | distributes such Contribution. 109 | 110 | 2.3. Limitations on Grant Scope 111 | 112 | The licenses granted in this Section 2 are the only rights granted under 113 | this License. No additional rights or licenses will be implied from the 114 | distribution or licensing of Covered Software under this License. 115 | Notwithstanding Section 2.1(b) above, no patent license is granted by a 116 | Contributor: 117 | 118 | (a) for any code that a Contributor has removed from Covered Software; 119 | or 120 | 121 | (b) for infringements caused by: (i) Your and any other third party's 122 | modifications of Covered Software, or (ii) the combination of its 123 | Contributions with other software (except as part of its Contributor 124 | Version); or 125 | 126 | (c) under Patent Claims infringed by Covered Software in the absence of 127 | its Contributions. 128 | 129 | This License does not grant any rights in the trademarks, service marks, 130 | or logos of any Contributor (except as may be necessary to comply with 131 | the notice requirements in Section 3.4). 132 | 133 | 2.4. Subsequent Licenses 134 | 135 | No Contributor makes additional grants as a result of Your choice to 136 | distribute the Covered Software under a subsequent version of this 137 | License (see Section 10.2) or under the terms of a Secondary License (if 138 | permitted under the terms of Section 3.3). 139 | 140 | 2.5. Representation 141 | 142 | Each Contributor represents that the Contributor believes its 143 | Contributions are its original creation(s) or it has sufficient rights 144 | to grant the rights to its Contributions conveyed by this License. 145 | 146 | 2.6. Fair Use 147 | 148 | This License is not intended to limit any rights You have under 149 | applicable copyright doctrines of fair use, fair dealing, or other 150 | equivalents. 151 | 152 | 2.7. Conditions 153 | 154 | Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted 155 | in Section 2.1. 156 | 157 | 3. Responsibilities 158 | ------------------- 159 | 160 | 3.1. Distribution of Source Form 161 | 162 | All distribution of Covered Software in Source Code Form, including any 163 | Modifications that You create or to which You contribute, must be under 164 | the terms of this License. You must inform recipients that the Source 165 | Code Form of the Covered Software is governed by the terms of this 166 | License, and how they can obtain a copy of this License. You may not 167 | attempt to alter or restrict the recipients' rights in the Source Code 168 | Form. 169 | 170 | 3.2. Distribution of Executable Form 171 | 172 | If You distribute Covered Software in Executable Form then: 173 | 174 | (a) such Covered Software must also be made available in Source Code 175 | Form, as described in Section 3.1, and You must inform recipients of 176 | the Executable Form how they can obtain a copy of such Source Code 177 | Form by reasonable means in a timely manner, at a charge no more 178 | than the cost of distribution to the recipient; and 179 | 180 | (b) You may distribute such Executable Form under the terms of this 181 | License, or sublicense it under different terms, provided that the 182 | license for the Executable Form does not attempt to limit or alter 183 | the recipients' rights in the Source Code Form under this License. 184 | 185 | 3.3. Distribution of a Larger Work 186 | 187 | You may create and distribute a Larger Work under terms of Your choice, 188 | provided that You also comply with the requirements of this License for 189 | the Covered Software. If the Larger Work is a combination of Covered 190 | Software with a work governed by one or more Secondary Licenses, and the 191 | Covered Software is not Incompatible With Secondary Licenses, this 192 | License permits You to additionally distribute such Covered Software 193 | under the terms of such Secondary License(s), so that the recipient of 194 | the Larger Work may, at their option, further distribute the Covered 195 | Software under the terms of either this License or such Secondary 196 | License(s). 197 | 198 | 3.4. Notices 199 | 200 | You may not remove or alter the substance of any license notices 201 | (including copyright notices, patent notices, disclaimers of warranty, 202 | or limitations of liability) contained within the Source Code Form of 203 | the Covered Software, except that You may alter any license notices to 204 | the extent required to remedy known factual inaccuracies. 205 | 206 | 3.5. Application of Additional Terms 207 | 208 | You may choose to offer, and to charge a fee for, warranty, support, 209 | indemnity or liability obligations to one or more recipients of Covered 210 | Software. However, You may do so only on Your own behalf, and not on 211 | behalf of any Contributor. You must make it absolutely clear that any 212 | such warranty, support, indemnity, or liability obligation is offered by 213 | You alone, and You hereby agree to indemnify every Contributor for any 214 | liability incurred by such Contributor as a result of warranty, support, 215 | indemnity or liability terms You offer. You may include additional 216 | disclaimers of warranty and limitations of liability specific to any 217 | jurisdiction. 218 | 219 | 4. Inability to Comply Due to Statute or Regulation 220 | --------------------------------------------------- 221 | 222 | If it is impossible for You to comply with any of the terms of this 223 | License with respect to some or all of the Covered Software due to 224 | statute, judicial order, or regulation then You must: (a) comply with 225 | the terms of this License to the maximum extent possible; and (b) 226 | describe the limitations and the code they affect. Such description must 227 | be placed in a text file included with all distributions of the Covered 228 | Software under this License. Except to the extent prohibited by statute 229 | or regulation, such description must be sufficiently detailed for a 230 | recipient of ordinary skill to be able to understand it. 231 | 232 | 5. Termination 233 | -------------- 234 | 235 | 5.1. The rights granted under this License will terminate automatically 236 | if You fail to comply with any of its terms. However, if You become 237 | compliant, then the rights granted under this License from a particular 238 | Contributor are reinstated (a) provisionally, unless and until such 239 | Contributor explicitly and finally terminates Your grants, and (b) on an 240 | ongoing basis, if such Contributor fails to notify You of the 241 | non-compliance by some reasonable means prior to 60 days after You have 242 | come back into compliance. Moreover, Your grants from a particular 243 | Contributor are reinstated on an ongoing basis if such Contributor 244 | notifies You of the non-compliance by some reasonable means, this is the 245 | first time You have received notice of non-compliance with this License 246 | from such Contributor, and You become compliant prior to 30 days after 247 | Your receipt of the notice. 248 | 249 | 5.2. If You initiate litigation against any entity by asserting a patent 250 | infringement claim (excluding declaratory judgment actions, 251 | counter-claims, and cross-claims) alleging that a Contributor Version 252 | directly or indirectly infringes any patent, then the rights granted to 253 | You by any and all Contributors for the Covered Software under Section 254 | 2.1 of this License shall terminate. 255 | 256 | 5.3. In the event of termination under Sections 5.1 or 5.2 above, all 257 | end user license agreements (excluding distributors and resellers) which 258 | have been validly granted by You or Your distributors under this License 259 | prior to termination shall survive termination. 260 | 261 | ************************************************************************ 262 | * * 263 | * 6. Disclaimer of Warranty * 264 | * ------------------------- * 265 | * * 266 | * Covered Software is provided under this License on an "as is" * 267 | * basis, without warranty of any kind, either expressed, implied, or * 268 | * statutory, including, without limitation, warranties that the * 269 | * Covered Software is free of defects, merchantable, fit for a * 270 | * particular purpose or non-infringing. The entire risk as to the * 271 | * quality and performance of the Covered Software is with You. * 272 | * Should any Covered Software prove defective in any respect, You * 273 | * (not any Contributor) assume the cost of any necessary servicing, * 274 | * repair, or correction. This disclaimer of warranty constitutes an * 275 | * essential part of this License. No use of any Covered Software is * 276 | * authorized under this License except under this disclaimer. * 277 | * * 278 | ************************************************************************ 279 | 280 | ************************************************************************ 281 | * * 282 | * 7. Limitation of Liability * 283 | * -------------------------- * 284 | * * 285 | * Under no circumstances and under no legal theory, whether tort * 286 | * (including negligence), contract, or otherwise, shall any * 287 | * Contributor, or anyone who distributes Covered Software as * 288 | * permitted above, be liable to You for any direct, indirect, * 289 | * special, incidental, or consequential damages of any character * 290 | * including, without limitation, damages for lost profits, loss of * 291 | * goodwill, work stoppage, computer failure or malfunction, or any * 292 | * and all other commercial damages or losses, even if such party * 293 | * shall have been informed of the possibility of such damages. This * 294 | * limitation of liability shall not apply to liability for death or * 295 | * personal injury resulting from such party's negligence to the * 296 | * extent applicable law prohibits such limitation. Some * 297 | * jurisdictions do not allow the exclusion or limitation of * 298 | * incidental or consequential damages, so this exclusion and * 299 | * limitation may not apply to You. * 300 | * * 301 | ************************************************************************ 302 | 303 | 8. Litigation 304 | ------------- 305 | 306 | Any litigation relating to this License may be brought only in the 307 | courts of a jurisdiction where the defendant maintains its principal 308 | place of business and such litigation shall be governed by laws of that 309 | jurisdiction, without reference to its conflict-of-law provisions. 310 | Nothing in this Section shall prevent a party's ability to bring 311 | cross-claims or counter-claims. 312 | 313 | 9. Miscellaneous 314 | ---------------- 315 | 316 | This License represents the complete agreement concerning the subject 317 | matter hereof. If any provision of this License is held to be 318 | unenforceable, such provision shall be reformed only to the extent 319 | necessary to make it enforceable. Any law or regulation which provides 320 | that the language of a contract shall be construed against the drafter 321 | shall not be used to construe this License against a Contributor. 322 | 323 | 10. Versions of the License 324 | --------------------------- 325 | 326 | 10.1. New Versions 327 | 328 | Mozilla Foundation is the license steward. Except as provided in Section 329 | 10.3, no one other than the license steward has the right to modify or 330 | publish new versions of this License. Each version will be given a 331 | distinguishing version number. 332 | 333 | 10.2. Effect of New Versions 334 | 335 | You may distribute the Covered Software under the terms of the version 336 | of the License under which You originally received the Covered Software, 337 | or under the terms of any subsequent version published by the license 338 | steward. 339 | 340 | 10.3. Modified Versions 341 | 342 | If you create software not governed by this License, and you want to 343 | create a new license for such software, you may create and use a 344 | modified version of this License if you rename the license and remove 345 | any references to the name of the license steward (except to note that 346 | such modified license differs from this License). 347 | 348 | 10.4. Distributing Source Code Form that is Incompatible With Secondary 349 | Licenses 350 | 351 | If You choose to distribute Source Code Form that is Incompatible With 352 | Secondary Licenses under the terms of this version of the License, the 353 | notice described in Exhibit B of this License must be attached. 354 | 355 | Exhibit A - Source Code Form License Notice 356 | ------------------------------------------- 357 | 358 | This Source Code Form is subject to the terms of the Mozilla Public 359 | License, v. 2.0. If a copy of the MPL was not distributed with this 360 | file, You can obtain one at http://mozilla.org/MPL/2.0/. 361 | 362 | If it is not possible or desirable to put the notice in a particular 363 | file, then You may include the notice in a location (such as a LICENSE 364 | file in a relevant directory) where a recipient would be likely to look 365 | for such a notice. 366 | 367 | You may add additional accurate notices of copyright ownership. 368 | 369 | Exhibit B - "Incompatible With Secondary Licenses" Notice 370 | --------------------------------------------------------- 371 | 372 | This Source Code Form is "Incompatible With Secondary Licenses", as 373 | defined by the Mozilla Public License, v. 2.0. 374 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # Leetcode Questions By Companies 2 | 3 | A list of LeetCode questions with the corresponding companies sorted by difficulty level. 4 | 5 | | **ID** | **Name** | **Difficulty.Level** | **Companies** | 6 | | --- | --- | --- | --- | 7 | | 717 | 1-bit and 2-bit Characters | Easy | Google | 8 | | 67 | Add Binary | Easy | Adobe, Amazon, Facebook, Google, Microsoft | 9 | | 258 | Add Digits | Easy | Adobe, Apple | 10 | | 415 | Add Strings | Easy | Apple, Facebook, Google, Microsoft | 11 | | 637 | Average of Levels in Binary Tree | Easy | Amazon, Facebook | 12 | | 844 | Backspace String Compare | Easy | Google | 13 | | 110 | Balanced Binary Tree | Easy | Amazon, Google | 14 | | 682 | Baseball Game | Easy | Amazon | 15 | | 121 | Best Time to Buy and Sell Stock | Easy | Facebook | 16 | | 122 | Best Time to Buy and Sell Stock II | Easy | Alibaba | 17 | | 595 | Big Countries | Easy | Adobe, Amazon, Google | 18 | | 704 | Binary Search | Easy | Google | 19 | | 107 | Binary Tree Level Order Traversal II | Easy | Microsoft | 20 | | 257 | Binary Tree Paths | Easy | Amazon, Facebook, Microsoft | 21 | | 859 | Buddy Strings | Easy | Google | 22 | | 70 | Climbing Stairs | Easy | Adobe, Alibaba, Amazon, Apple, Facebook, Microsoft | 23 | | 270 | Closest Binary Search Tree Value | Easy | Google | 24 | | 175 | Combine Two Tables | Easy | Adobe, Amazon, Apple, Facebook, Google | 25 | | 427 | Construct Quad Tree | Easy | Apple | 26 | | 217 | Contains Duplicate | Easy | Amazon | 27 | | 219 | Contains Duplicate II | Easy | Adobe, Google | 28 | | 405 | Convert a Number to Hexadecimal | Easy | Facebook | 29 | | 538 | Convert BST to Greater Tree | Easy | Amazon | 30 | | 108 | Convert Sorted Array to Binary Search Tree | Easy | Adobe, Apple | 31 | | 38 | Count and Say | Easy | Adobe, Amazon, Google, Microsoft | 32 | | 696 | Count Binary Substrings | Easy | Adobe | 33 | | 204 | Count Primes | Easy | Adobe, Amazon, Apple, Google, Microsoft | 34 | | 183 | Customers Who Never Order | Easy | Amazon | 35 | | 237 | Delete Node in a Linked List | Easy | Apple | 36 | | 706 | Design HashMap | Easy | Adobe, Amazon, Apple, Microsoft | 37 | | 707 | Design Linked List | Easy | Amazon | 38 | | 543 | Diameter of Binary Tree | Easy | Adobe | 39 | | 690 | Employee Importance | Easy | Google | 40 | | 181 | Employees Earning More Than Their Managers | Easy | Amazon, Facebook | 41 | | 171 | Excel Sheet Column Number | Easy | Akuna Capital | 42 | | 168 | Excel Sheet Column Title | Easy | Akuna Capital | 43 | | 172 | Factorial Trailing Zeroes | Easy | Adobe, Microsoft | 44 | | 509 | Fibonacci Number | Easy | Adobe, Amazon, Microsoft | 45 | | 438 | Find All Anagrams in a String | Easy | Amazon, Facebook, Google | 46 | | 448 | Find All Numbers Disappeared in an Array | Easy | Apple | 47 | | 760 | Find Anagram Mappings | Easy | Google | 48 | | 724 | Find Pivot Index | Easy | Amazon, Apple, Facebook, Google, Microsoft | 49 | | 997 | Find the Town Judge | Easy | Amazon | 50 | | 278 | First Bad Version | Easy | Facebook, Google | 51 | | 387 | First Unique Character in a String | Easy | Amazon, Apple, Facebook, Google, Microsoft | 52 | | 412 | Fizz Buzz | Easy | Apple | 53 | | 832 | Flipping an Image | Easy | Google | 54 | | 733 | Flood Fill | Easy | Amazon, Google | 55 | | 597 | Friend Requests I: Overall Acceptance Rate | Easy | Facebook | 56 | | 824 | Goat Latin | Easy | Facebook | 57 | | 374 | Google - LeetCodeGuess Number Higher or Lower | Easy | Google | 58 | | 933 | Google - LeetCodeNumber of Recent Calls | Easy | Google | 59 | | 572 | Google - LeetCodeSubtree of Another Tree | Easy | Google | 60 | | 202 | Happy Number | Easy | Amazon, Apple, Facebook | 61 | | 475 | Heaters | Easy | Google | 62 | | 198 | House Robber | Easy | Adobe, Amazon, Apple, Facebook, Google, Microsoft | 63 | | 661 | Image Smoother | Easy | Apple | 64 | | 232 | Implement Queue using Stacks | Easy | Apple, Microsoft | 65 | | 225 | Implement Stack using Queues | Easy | Microsoft | 66 | | 28 | Implement strStr | Easy | Adobe, Amazon, Apple, Facebook, Google, Microsoft | 67 | | 897 | Increasing Order Search Tree | Easy | Facebook | 68 | | 349 | Intersection of Two Arrays | Easy | Amazon, Apple, Facebook, Google, Microsoft | 69 | | 350 | Intersection of Two Arrays II | Easy | Amazon | 70 | | 160 | Intersection of Two Linked Lists | Easy | Amazon | 71 | | 226 | Invert Binary Tree | Easy | Adobe, Amazon, Facebook | 72 | | 751 | IP to CIDR | Easy | Airbnb | 73 | | 463 | Island Perimeter | Easy | Amazon, Apple, Facebook, Google | 74 | | 205 | Isomorphic Strings | Easy | Amazon, Google | 75 | | 771 | Jewels and Stones | Easy | Adobe, Alibaba, Amazon, Apple, Google | 76 | | 532 | K-diff Pairs in an Array | Easy | Amazon | 77 | | 703 | Kth Largest Element in a Stream | Easy | Amazon, Facebook, Google | 78 | | 872 | Leaf-Similar Trees | Easy | Facebook, Google | 79 | | 860 | Lemonade Change | Easy | Amazon | 80 | | 58 | Length of Last Word | Easy | Adobe | 81 | | 784 | Letter Case Permutation | Easy | Microsoft | 82 | | 482 | License Key Formatting | Easy | Amazon, Google | 83 | | 141 | Linked List Cycle | Easy | Adobe, Akuna Capital, Alibaba, Amazon, Apple, Facebook, Google, Microsoft | 84 | | 359 | Logger Rate Limiter | Easy | Facebook, Google | 85 | | 14 | Longest Common Prefix | Easy | Adobe, Apple, Google, Microsoft | 86 | | 674 | Longest Continuous Increasing Subsequence | Easy | Google | 87 | | 409 | Longest Palindrome | Easy | Amazon | 88 | | 687 | Longest Univalue Path | Easy | Amazon | 89 | | 720 | Longest Word in Dictionary | Easy | Amazon, Google | 90 | | 235 | Lowest Common Ancestor of a Binary Search Tree | Easy | Adobe | 91 | | 840 | Magic Squares In Grid | Easy | Google | 92 | | 169 | Majority Element | Easy | Adobe, Amazon, Apple, Google, Microsoft | 93 | | 485 | Max Consecutive Ones | Easy | Amazon | 94 | | 716 | Max Stack | Easy | Facebook | 95 | | 849 | Maximize Distance to Closest Person | Easy | Google | 96 | | 104 | Maximum Depth of Binary Tree | Easy | Apple, Facebook, Google | 97 | | 559 | Maximum Depth of N-ary Tree | Easy | Amazon, Google | 98 | | 628 | Maximum Product of Three Numbers | Easy | Amazon, Facebook | 99 | | 53 | Maximum Subarray | Easy | Adobe, Alibaba, Amazon, Apple, Facebook, Microsoft | 100 | | 252 | Meeting Rooms | Easy | Amazon, Facebook | 101 | | 88 | Merge Sorted Array | Easy | Adobe, Amazon, Facebook, Microsoft | 102 | | 617 | Merge Two Binary Trees | Easy | Amazon | 103 | | 21 | Merge Two Sorted Lists | Easy | Airbnb, Alibaba | 104 | | 746 | Min Cost Climbing Stairs | Easy | Amazon | 105 | | 155 | Min Stack | Easy | Adobe, Amazon, Apple, Facebook, Google, Microsoft | 106 | | 111 | Minimum Depth of Binary Tree | Easy | Adobe, Amazon, Microsoft | 107 | | 783 | Minimum Distance Between BST Nodes | Easy | Amazon | 108 | | 599 | Minimum Index Sum of Two Lists | Easy | Amazon | 109 | | 268 | Missing Number | Easy | Adobe, Amazon, Apple | 110 | | 896 | Monotonic Array | Easy | Facebook | 111 | | 819 | Most Common Word | Easy | Amazon, Google, Microsoft | 112 | | 283 | Move Zeroes | Easy | Adobe, Apple, Facebook, Google, Microsoft | 113 | | 346 | Moving Average from Data Stream | Easy | Google | 114 | | 429 | N-ary Tree Level Order Traversal | Easy | Google | 115 | | 339 | Nested List Weight Sum | Easy | Amazon | 116 | | 496 | Next Greater Element I | Easy | Amazon, Google | 117 | | 665 | Non-decreasing Array | Easy | Google | 118 | | 400 | Nth Digit | Easy | Adobe, Google | 119 | | 476 | Number Complement | Easy | Google | 120 | | 191 | Number of 1 Bits | Easy | Amazon, Apple, Google, Microsoft | 121 | | 447 | Number of Boomerangs | Easy | Amazon, Google | 122 | | 806 | Number of Lines To Write String | Easy | Google | 123 | | 1013 | Pairs of Songs With Total Durations Divisible by 60 | Easy | Amazon | 124 | | 234 | Palindrome Linked List | Easy | Amazon, Google | 125 | | 9 | Palindrome Number | Easy | Adobe, Alibaba, Amazon, Apple, Facebook, Google, Microsoft | 126 | | 266 | Palindrome Permutation | Easy | Amazon, Facebook, Google, Microsoft | 127 | | 118 | Pascal's Triangle | Easy | Amazon, Facebook, Google, Microsoft | 128 | | 119 | Pascal's Triangle II | Easy | Adobe, Amazon, Google | 129 | | 112 | Path Sum | Easy | Amazon | 130 | | 437 | Path Sum III | Easy | Amazon, Facebook | 131 | | 852 | Peak Index in a Mountain Array | Easy | Amazon, Google | 132 | | 507 | Perfect Number | Easy | Amazon | 133 | | 66 | Plus One | Easy | Amazon, Facebook, Google, Microsoft | 134 | | 830 | Positions of Large Groups | Easy | Adobe, Google | 135 | | 326 | Power of Three | Easy | Apple | 136 | | 231 | Power of Two | Easy | Amazon | 137 | | 157 | Read N Characters Given Read4 | Easy | Facebook, Google | 138 | | 836 | Rectangle Overlap | Easy | Adobe, Amazon, Microsoft | 139 | | 26 | Remove Duplicates from Sorted Array | Easy | Amazon, Apple, Facebook, Google, Microsoft | 140 | | 83 | Remove Duplicates from Sorted List | Easy | Apple, Google | 141 | | 27 | Remove Element | Easy | Amazon, Google | 142 | | 203 | Remove Linked List Elements | Easy | Adobe, Amazon, Microsoft | 143 | | 937 | Reorder Log Files | Easy | Amazon | 144 | | 686 | Repeated String Match | Easy | Facebook, Google | 145 | | 190 | Reverse Bits | Easy | Amazon, Apple | 146 | | 7 | Reverse Integer | Easy | Adobe, Alibaba, Amazon, Facebook, Google, Microsoft | 147 | | 206 | Reverse Linked List | Easy | Adobe, Alibaba, Facebook, Google, Microsoft | 148 | | 917 | Reverse Only Letters | Easy | Microsoft | 149 | | 344 | Reverse String | Easy | Adobe, Amazon, Apple, Facebook, Google, Microsoft | 150 | | 541 | Reverse String II | Easy | Microsoft | 151 | | 557 | Reverse Words in a String III | Easy | Apple, Microsoft | 152 | | 657 | Robot Return to Origin | Easy | Adobe, Amazon | 153 | | 13 | Roman to Integer | Easy | Adobe, Amazon, Apple, Facebook, Google, Microsoft | 154 | | 189 | Rotate Array | Easy | Amazon | 155 | | 796 | Rotate String | Easy | Amazon | 156 | | 788 | Rotated Digits | Easy | Google | 157 | | 100 | Same Tree | Easy | Amazon, Apple, Facebook, Google | 158 | | 700 | Search in a Binary Search Tree | Easy | Google | 159 | | 35 | Search Insert Position | Easy | Adobe | 160 | | 176 | Second Highest Salary | Easy | Adobe, Apple | 161 | | 671 | Second Minimum Node In a Binary Tree | Easy | Microsoft | 162 | | 734 | Sentence Similarity | Easy | Google | 163 | | 821 | Shortest Distance to a Character | Easy | Google | 164 | | 243 | Shortest Word Distance | Easy | Amazon, Google | 165 | | 800 | Similar RGB Color | Easy | Google | 166 | | 136 | Single Number | Easy | Amazon | 167 | | 905 | Sort Array By Parity | Easy | Adobe, Amazon, Google, Microsoft | 168 | | 69 | Sqrt(x) | Easy | Amazon, Apple, Facebook, Google, Microsoft | 169 | | 977 | Squares of a Sorted Array | Easy | Adobe | 170 | | 443 | String Compression | Easy | Amazon | 171 | | 246 | Strobogrammatic Number | Easy | Facebook, Google | 172 | | 811 | Subdomain Visit Count | Easy | Google | 173 | | 404 | Sum of Left Leaves | Easy | Amazon | 174 | | 1022 | Sum of Root To Leaf Binary Numbers | Easy | Amazon | 175 | | 371 | Sum of Two Integers | Easy | Facebook, Microsoft | 176 | | 101 | Symmetric Tree | Easy | Amazon, Apple, Facebook, Google, Microsoft | 177 | | 195 | Tenth Line | Easy | Adobe, Apple, Google | 178 | | 414 | Third Maximum Number | Easy | Facebook, Google, Microsoft | 179 | | 709 | To Lower Case | Easy | Adobe, Amazon, Apple | 180 | | 766 | Toeplitz Matrix | Easy | Facebook, Google | 181 | | 669 | Trim a Binary Search Tree | Easy | Amazon | 182 | | 1 | Two Sum | Easy | Adobe, Aetion, Affirm, Airbnb, Alibaba, Amazon, Apple, Facebook, Google, Microsoft | 183 | | 167 | Two Sum II - Input array is sorted | Easy | Adobe, Amazon, Apple, Facebook, Google, Microsoft | 184 | | 170 | Two Sum III - Data structure design | Easy | Facebook | 185 | | 653 | Two Sum IV - Input is a BST | Easy | Google | 186 | | 263 | Ugly Number | Easy | Adobe | 187 | | 929 | Unique Email Addresses | Easy | Adobe, Amazon, Apple, Google, Microsoft | 188 | | 804 | Unique Morse Code Words | Easy | Apple | 189 | | 242 | Valid Anagram | Easy | Amazon, Apple, Facebook, Google, Microsoft | 190 | | 941 | Valid Mountain Array | Easy | Google | 191 | | 125 | Valid Palindrome | Easy | Amazon, Apple, Facebook, Google, Microsoft | 192 | | 680 | Valid Palindrome II | Easy | Facebook | 193 | | 20 | Valid Parentheses | Easy | Adobe, Akuna Capital, Amazon, Apple, Facebook, Google, Microsoft | 194 | | 193 | Valid Phone Numbers | Easy | Adobe | 195 | | 953 | Verifying an Alien Dictionary | Easy | Facebook | 196 | | 290 | Word Pattern | Easy | Google, Microsoft | 197 | | 914 | X of a Kind in a Deck of Cards | Easy | Google | 198 | | 542 | 01 Matrix | Medium | Google | 199 | | 15 | 3Sum | Medium | Adobe, Akuna Capital, Amazon, Apple, Google, Microsoft, Alibaba | 200 | | 16 | 3Sum Closest | Medium | Amazon, Apple, Google, Microsoft | 201 | | 259 | 3Sum Smaller | Medium | Google | 202 | | 18 | 4Sum | Medium | Adobe, Amazon, Apple, Facebook | 203 | | 454 | 4Sum II | Medium | Amazon | 204 | | 721 | Accounts Merge | Medium | Facebook, Google | 205 | | 211 | Add and Search Word - Data structure design | Medium | Facebook | 206 | | 616 | Add Bold Tag in String | Medium | Google | 207 | | 2 | Add Two Numbers | Medium | Adobe, Aetion, Airbnb, Alibaba, Amazon, Apple, Facebook, Google | 208 | | 445 | Add Two Numbers II | Medium | Facebook, Amazon | 209 | | 863 | All Nodes Distance K in Binary Tree | Medium | Amazon, Google, Microsoft | 210 | | 797 | All Paths From Source to Target | Medium | Amazon | 211 | | 894 | All Possible Full Binary Trees | Medium | Google | 212 | | 351 | Android Unlock Patterns | Medium | Google | 213 | | 227 | Basic Calculator II | Medium | Amazon, Apple, Facebook, Google, Microsoft | 214 | | 419 | Battleships in a Board | Medium | Facebook, Google, Microsoft | 215 | | 714 | Best Time to Buy and Sell Stock with Transaction Fee | Medium | Facebook | 216 | | 173 | Binary Search Tree Iterator | Medium | Google | 217 | | 94 | Binary Tree Inorder Traversal | Medium | Adobe, Google, Microsoft | 218 | | 102 | Binary Tree Level Order Traversal | Medium | Apple, Google | 219 | | 298 | Binary Tree Longest Consecutive Sequence | Medium | Facebook | 220 | | 549 | Binary Tree Longest Consecutive Sequence II | Medium | Google | 221 | | 144 | Binary Tree Preorder Traversal | Medium | Google | 222 | | 199 | Binary Tree Right Side View | Medium | Adobe, Google, Amazon | 223 | | 314 | Binary Tree Vertical Order Traversal | Medium | Microsoft | 224 | | 103 | Binary Tree Zigzag Level Order Traversal | Medium | Adobe, Google | 225 | | 201 | Bitwise AND of Numbers Range | Medium | Adobe | 226 | | 881 | Boats to Save People | Medium | Google | 227 | | 361 | Bomb Enemy | Medium | Amazon, Google | 228 | | 545 | Boundary of Binary Tree | Medium | Amazon | 229 | | 554 | Brick Wall | Medium | Facebook | 230 | | 319 | Bulb Switcher | Medium | Facebook | 231 | | 299 | Bulls and Cows | Medium | Amazon, Google | 232 | | 464 | Can I Win | Medium | Google | 233 | | 723 | Candy Crush | Medium | Google | 234 | | 1011 | Capacity To Ship Packages Within D Days | Medium | Google | 235 | | 853 | Car Fleet | Medium | Google | 236 | | 799 | Champagne Tower | Medium | Google | 237 | | 787 | Cheapest Flights Within K Stops | Medium | Airbnb, Microsoft | 238 | | 958 | Check Completeness of a Binary Tree | Medium | Facebook, Microsoft | 239 | | 457 | Circular Array Loop | Medium | Google | 240 | | 133 | Clone Graph | Medium | Amazon, Facebook | 241 | | 742 | Closest Leaf in a Binary Tree | Medium | Google | 242 | | 322 | Coin Change | Medium | Adobe, Airbnb, Amazon, Apple, Facebook, Microsoft | 243 | | 518 | Coin Change 2 | Medium | Amazon, Facebook, Google, Microsoft | 244 | | 39 | Combination Sum | Medium | Airbnb, Apple, Facebook, Google, Microsoft | 245 | | 40 | Combination Sum II | Medium | Microsoft | 246 | | 377 | Combination Sum IV | Medium | Facebook | 247 | | 77 | Combinations | Medium | Facebook, Google, Microsoft | 248 | | 165 | Compare Version Numbers | Medium | Amazon, Apple, Microsoft | 249 | | 180 | Consecutive Numbers | Medium | Facebook | 250 | | 1008 | Construct Binary Search Tree from Preorder | Medium | Facebook | 251 | | 106 | Construct Binary Tree from Inorder and Postorder | Medium | Microsoft | 252 | | 105 | Construct Binary Tree from Preorder and Inorder | Medium | Facebook | 253 | | 889 | Construct Binary Tree from Preorder and PostorderTraversal | Medium | Facebook, Google | 254 | | 536 | Construct Binary Tree from String | Medium | Facebook | 255 | | 11 | Container With Most Water | Medium | Airbnb, Alibaba | 256 | | 523 | Continuous Subarray Sum | Medium | Facebook, Microsoft | 257 | | 426 | Convert Binary Search Tree to Sorted Doubly LinkedList | Medium | Facebook, Google, Microsoft | 258 | | 109 | Convert Sorted List to Binary Search Tree | Medium | Facebook, Microsoft | 259 | | 138 | Copy List with Random Pointer | Medium | Alibaba, Facebook | 260 | | 222 | Count Complete Tree Nodes | Medium | Facebook, Google | 261 | | 250 | Count Univalue Subtrees | Medium | Amazon | 262 | | 338 | Counting Bits | Medium | Apple | 263 | | 207 | Course Schedule | Medium | Amazon, Facebook, Google, Microsoft | 264 | | 210 | Course Schedule II | Medium | Amazon, Facebook, Google, Microsoft | 265 | | 791 | Custom Sort String | Medium | Amazon, Facebook | 266 | | 739 | Daily Temperatures | Medium | Amazon, Google, Microsoft | 267 | | 394 | Decode String | Medium | Amazon, appdynamics, Apple, Facebook, Google, Microsoft | 268 | | 91 | Decode Ways | Medium | Adobe, Amazon, Apple, Facebook, Google, Microsoft | 269 | | 450 | Delete Node in a BST | Medium | Google | 270 | | 583 | Delete Operation for Two Strings | Medium | Amazon | 271 | | 184 | Department Highest Salary | Medium | Amazon | 272 | | 622 | Design Circular Queue | Medium | Amazon, Facebook | 273 | | 362 | Design Hit Counter | Medium | Amazon, Google, Microsoft | 274 | | 635 | Design Log Storage System | Medium | Google | 275 | | 379 | Design Phone Directory | Medium | Google | 276 | | 353 | Design Snake Game | Medium | Apple, Amazon, Google | 277 | | 348 | Design Tic-Tac-Toe | Medium | Apple, Facebook, Microsoft | 278 | | 498 | Diagonal Traverse | Medium | Facebook, Google | 279 | | 241 | Different Ways to Add Parentheses | Medium | Google | 280 | | 979 | Distribute Coins in Binary Tree | Medium | Amazon, Google, Microsoft | 281 | | 29 | Divide Two Integers | Medium | Adobe, Amazon, Facebook, Google, Microsoft | 282 | | 271 | Encode and Decode Strings | Medium | Google | 283 | | 535 | Encode and Decode TinyURL | Medium | Adobe | 284 | | 663 | Equal Tree Partition | Medium | Facebook | 285 | | 399 | Evaluate Division | Medium | Adobe, Amazon, Facebook, Google | 286 | | 150 | Evaluate Reverse Polish Notation | Medium | Microsoft | 287 | | 855 | Exam Room | Medium | Google | 288 | | 626 | Exchange Seats | Medium | Amazon | 289 | | 636 | Exclusive Time of Functions | Medium | Microsoft | 290 | | 809 | Expressive Words | Medium | Google | 291 | | 442 | Find All Duplicates in an Array | Medium | Amazon, Microsoft | 292 | | 833 | Find And Replace in String | Medium | Google | 293 | | 890 | Find and Replace Pattern | Medium | Apple | 294 | | 609 | Find Duplicate File in System | Medium | Amazon | 295 | | 652 | Find Duplicate Subtrees | Medium | Google | 296 | | 34 | Find First and Last Position of Element in Sorted | Medium | Facebook | 297 | | 658 | Find K Closest Elements | Medium | Facebook | 298 | | 373 | Find K Pairs with Smallest Sums | Medium | Amazon, Apple, Google, Microsoft | 299 | | 366 | Find Leaves of Binary Tree | Medium | Amazon, Google | 300 | | 153 | Find Minimum in Rotated Sorted Array | Medium | Google | 301 | | 162 | Find Peak Element | Medium | Amazon, Facebook, Microsoft, Google | 302 | | 277 | Find the Celebrity | Medium | Amazon, Facebook, Microsoft | 303 | | 287 | Find the Duplicate Number | Medium | Adobe, Amazon, Google, Microsoft | 304 | | 251 | Flatten 2D Vector | Medium | Airbnb | 305 | | 430 | Flatten a Multilevel Doubly Linked List | Medium | Amazon | 306 | | 114 | Flatten Binary Tree to Linked List | Medium | Adobe, Amazon, Microsoft | 307 | | 341 | Flatten Nested List Iterator | Medium | Airbnb | 308 | | 951 | Flip Equivalent Binary Trees | Medium | Google | 309 | | 294 | Flip Game II | Medium | Google | 310 | | 926 | Flip String to Monotone Increasing | Medium | Google | 311 | | 166 | Fraction to Recurring Decimal | Medium | Facebook | 312 | | 547 | Friend Circles | Medium | Amazon, Facebook, Microsoft | 313 | | 825 | Friends Of Appropriate Ages | Medium | Facebook | 314 | | 904 | Fruit Into Baskets | Medium | Amazon, Google | 315 | | 289 | Game of Life | Medium | Amazon, Microsoft | 316 | | 134 | Gas Station | Medium | Amazon, Google, Microsoft | 317 | | 320 | Generalized Abbreviation | Medium | Google | 318 | | 22 | Generate Parentheses | Medium | Adobe, Aetion | 319 | | 478 | Generate Random Point in a Circle | Medium | Facebook | 320 | | 129 | Google - LeetCodeSum Root to Leaf Numbers | Medium | Google | 321 | | 261 | Graph Valid Tree | Medium | Amazon, Google | 322 | | 89 | Gray Code | Medium | Google | 323 | | 49 | Group Anagrams | Medium | Adobe, Affirm, Alibaba, Amazon, Apple, Facebook, Google, Microsoft | 324 | | 249 | Group Shifted Strings | Medium | Apple | 325 | | 375 | Guess Number Higher or Lower II | Medium | Google | 326 | | 274 | H-Index | Medium | Google | 327 | | 846 | Hand of Straights | Medium | Google | 328 | | 337 | House Robber III | Medium | Amazon, Facebook, Google | 329 | | 835 | Image Overlap | Medium | Google | 330 | | 676 | Implement Magic Dictionary | Medium | Google | 331 | | 470 | Implement Rand10 Using Rand7 | Medium | Google | 332 | | 208 | Implement Trie (Prefix Tree) | Medium | Amazon | 333 | | 491 | Increasing Subsequences | Medium | Facebook | 334 | | 334 | Increasing Triplet Subsequence | Medium | Amazon, Google, Facebook | 335 | | 285 | Inorder Successor in BST | Medium | Facebook, Microsoft | 336 | | 510 | Inorder Successor in BST II | Medium | Google | 337 | | 380 | Insert Delete GetRandom O(1) | Medium | Microsoft | 338 | | 701 | Insert into a Binary Search Tree | Medium | Microsoft | 339 | | 708 | Insert into a Cyclic Sorted List | Medium | Amazon, Facebook, Google, Microsoft | 340 | | 343 | Integer Break | Medium | Google | 341 | | 397 | Integer Replacement | Medium | Amazon | 342 | | 12 | Integer to Roman | Medium | Adobe, Amazon, Apple, Google, Microsoft | 343 | | 986 | Interval List Intersections | Medium | Facebook, Google | 344 | | 785 | Is Graph Bipartite? | Medium | Amazon, Apple, Facebook, Google, Microsoft | 345 | | 392 | Is Subsequence | Medium | Facebook, Google | 346 | | 55 | Jump Game | Medium | Amazon, Apple, Facebook, Google, Microsoft | 347 | | 973 | K Closest Points to Origin | Medium | Amazon, Apple, Facebook, Google, Microsoft | 348 | | 841 | Keys and Rooms | Medium | Amazon | 349 | | 582 | Kill Process | Medium | Apple | 350 | | 935 | Knight Dialer | Medium | Facebook, Microsoft | 351 | | 688 | Knight Probability in Chessboard | Medium | Facebook, Google, Microsoft | 352 | | 215 | Kth Largest Element in an Array | Medium | Facebook | 353 | | 230 | Kth Smallest Element in a BST | Medium | Amazon | 354 | | 378 | Kth Smallest Element in a Sorted Matrix | Medium | Apple | 355 | | 333 | Largest BST Subtree | Medium | Amazon, Google, Microsoft | 356 | | 368 | Largest Divisible Subset | Medium | Adobe, Google | 357 | | 179 | Largest Number | Medium | Amazon, Apple | 358 | | 17 | Letter Combinations of a Phone Number | Medium | Airbnb, Apple, Facebook | 359 | | 386 | Lexicographical Numbers | Medium | Google | 360 | | 817 | Linked List Components | Medium | Google | 361 | | 142 | Linked List Cycle II | Medium | Apple, Google, Microsoft | 362 | | 382 | Linked List Random Node | Medium | Apple, Facebook | 363 | | 388 | Longest Absolute File Path | Medium | Google | 364 | | 300 | Longest Increasing Subsequence | Medium | Adobe, Airbnb, Amazon, Apple, Facebook, Google, Microsoft | 365 | | 562 | Longest Line of Consecutive One in Matrix | Medium | Google | 366 | | 845 | Longest Mountain in Array | Medium | Google | 367 | | 516 | Longest Palindromic Subsequence | Medium | Apple, Microsoft | 368 | | 5 | Longest Palindromic Substring | Medium | Alibaba | 369 | | 424 | Longest Repeating Character Replacement | Medium | Google | 370 | | 395 | Longest Substring with At Least K RepeatingCharacters | Medium | Facebook, Google | 371 | | 3 | Longest Substring Without Repeating Characters | Medium | Akuna Capital, Alibaba | 372 | | 978 | Longest Turbulent Subarray | Medium | Amazon | 373 | | 524 | Longest Word in Dictionary through Deleting | Medium | Google | 374 | | 236 | Lowest Common Ancestor of a Binary Tree | Medium | Google | 375 | | 229 | Majority Element II | Medium | Amazon | 376 | | 695 | Max Area of Island | Medium | Adobe, Affirm, Alibaba, Amazon, Facebook, Google, Microsoft | 377 | | 769 | Max Chunks To Make Sorted | Medium | Google | 378 | | 487 | Max Consecutive Ones II | Medium | Google | 379 | | 1004 | Max Consecutive Ones III | Medium | Facebook | 380 | | 807 | Max Increase to Keep City Skyline | Medium | Google | 381 | | 221 | Maximal Square | Medium | Google | 382 | | 654 | Maximum Binary Tree | Medium | Amazon | 383 | | 318 | Maximum Product of Word Lengths | Medium | Google | 384 | | 152 | Maximum Product Subarray | Medium | Adobe | 385 | | 325 | Maximum Size Subarray Sum Equals k | Medium | Facebook | 386 | | 918 | Maximum Sum Circular Subarray | Medium | Facebook | 387 | | 670 | Maximum Swap | Medium | Facebook | 388 | | 662 | Maximum Width of Binary Tree | Medium | Google | 389 | | 253 | Meeting Rooms II | Medium | Amazon, Facebook, Google, Microsoft | 390 | | 56 | Merge Intervals | Medium | Adobe, Amazon, Apple, Facebook, Google, Microsoft | 391 | | 529 | Minesweeper | Medium | Google | 392 | | 921 | Minimum Add to Make Parentheses Valid | Medium | Facebook | 393 | | 939 | Minimum Area Rectangle | Medium | Google | 394 | | 983 | Minimum Cost For Tickets | Medium | Amazon | 395 | | 1007 | Minimum Domino Rotations For Equal Row | Medium | Google | 396 | | 931 | Minimum Falling Path Sum | Medium | Google | 397 | | 433 | Minimum Genetic Mutation | Medium | Google | 398 | | 310 | Minimum Height Trees | Medium | Google | 399 | | 452 | Minimum Number of Arrows to Burst Balloons | Medium | Facebook | 400 | | 64 | Minimum Path Sum | Medium | Adobe, Amazon, Google, Microsoft | 401 | | 209 | Minimum Size Subarray Sum | Medium | Google, Microsoft | 402 | | 539 | Minimum Time Difference | Medium | Google | 403 | | 163 | Missing Ranges | Medium | Amazon | 404 | | 508 | Most Frequent Subtree Sum | Medium | Amazon | 405 | | 947 | Most Stones Removed with Same Row or Column | Medium | Google | 406 | | 43 | Multiply Strings | Medium | Amazon, Apple, Facebook, Google, Microsoft | 407 | | 729 | My Calendar I | Medium | Amazon, Google, Microsoft | 408 | | 731 | My Calendar II | Medium | Amazon, Google | 409 | | 743 | Network Delay Time | Medium | Amazon | 410 | | 681 | Next Closest Time | Medium | Facebook, Google | 411 | | 503 | Next Greater Element II | Medium | Microsoft | 412 | | 556 | Next Greater Element III | Medium | Amazon | 413 | | 1019 | Next Greater Node In Linked List | Medium | Amazon | 414 | | 31 | Next Permutation | Medium | Adobe, Amazon, Apple, Facebook, Google, Microsoft | 415 | | 435 | Non-overlapping Intervals | Medium | Apple, Google | 416 | | 177 | Nth Highest Salary | Medium | Adobe, Amazon, Apple, Facebook | 417 | | 750 | Number Of Corner Rectangles | Medium | Google | 418 | | 694 | Number of Distinct Islands | Medium | Amazon, Facebook, Google, Microsoft | 419 | | 200 | Number of Islands | Medium | Adobe, Affirm, Alibaba, Amazon, appdynamics, Facebook, Google, Microsoft | 420 | | 673 | Number of Longest Increasing Subsequence | Medium | Amazon, Facebook | 421 | | 792 | Number of Matching Subsequences | Medium | Google | 422 | | 328 | Odd Even Linked List | Medium | Amazon, Google, Microsoft | 423 | | 161 | One Edit Distance | Medium | Facebook, Microsoft | 424 | | 911 | Online Election | Medium | Apple, Google | 425 | | 752 | Open the Lock | Medium | Facebook, Google | 426 | | 544 | Output Contest Matches | Medium | Google | 427 | | 417 | Pacific Atlantic Water Flow | Medium | Google, Microsoft | 428 | | 131 | Palindrome Partitioning | Medium | Adobe, Amazon | 429 | | 647 | Palindromic Substrings | Medium | Adobe, Amazon, Facebook, Google, Microsoft | 430 | | 416 | Partition Equal Subset Sum | Medium | Facebook, Google, Microsoft | 431 | | 86 | Partition List | Medium | Amazon, Microsoft | 432 | | 698 | Partition to K Equal Sum Subsets | Medium | Google | 433 | | 113 | Path Sum II | Medium | Amazon, appdynamics, Facebook, Google | 434 | | 284 | Peeking Iterator | Medium | Google | 435 | | 279 | Perfect Squares | Medium | Adobe, Amazon, Facebook, Google | 436 | | 567 | Permutation in String | Medium | Facebook, Google | 437 | | 60 | Permutation Sequence | Medium | Amazon, Google | 438 | | 46 | Permutations | Medium | Adobe, Amazon, Apple, Facebook, Google, Microsoft | 439 | | 47 | Permutations II | Medium | Adobe, Amazon, Facebook | 440 | | 369 | Plus One Linked List | Medium | Amazon, Google | 441 | | 117 | Populating Next Right Pointers in Each Node II | Medium | Amazon, Facebook, Google, Microsoft | 442 | | 116 | Populating Next Right Pointers in Each Node | Medium | Facebook | 443 | | 886 | Possible Bipartition | Medium | Facebook | 444 | | 755 | Pour Water | Medium | Airbnb | 445 | | 50 | Pow(x, n) | Medium | Adobe, Alibaba, Amazon, Apple, Facebook, Microsoft | 446 | | 486 | Predict the Winner | Medium | Google | 447 | | 655 | Print Binary Tree | Medium | Microsoft | 448 | | 957 | Prison Cells After N Days | Medium | Amazon | 449 | | 238 | Product of Array Except Self | Medium | Adobe, Amazon, Apple, Facebook, Google, Microsoft | 450 | | 756 | Pyramid Transition Matrix | Medium | Airbnb | 451 | | 406 | Queue Reconstruction by Height | Medium | Amazon, Google | 452 | | 398 | Random Pick Index | Medium | Facebook, Google | 453 | | 528 | Random Pick with Weight | Medium | Google, Microsoft | 454 | | 497 | Random Point in Non-overlapping Rectangles | Medium | Google | 455 | | 370 | Range Addition | Medium | Google | 456 | | 938 | Range Sum of BST | Medium | Google | 457 | | 307 | Range Sum Query - Mutable | Medium | Facebook, Google | 458 | | 304 | Range Sum Query 2D - Immutable | Medium | Facebook, Google, Microsoft | 459 | | 178 | Rank Scores | Medium | Amazon, Apple | 460 | | 332 | Reconstruct Itinerary | Medium | Amazon, Facebook, Google, Microsoft | 461 | | 223 | Rectangle Area | Medium | Microsoft | 462 | | 684 | Redundant Connection | Medium | Google | 463 | | 722 | Remove Comments | Medium | Amazon, Facebook, Google, Microsoft | 464 | | 80 | Remove Duplicates from Sorted Array II | Medium | Google | 465 | | 82 | Remove Duplicates from Sorted List II | Medium | Google | 466 | | 402 | Remove K Digits | Medium | Adobe, Amazon, Facebook, Microsoft | 467 | | 19 | Remove Nth Node From End of List | Medium | Facebook | 468 | | 143 | Reorder List | Medium | Amazon, Facebook, Google, Microsoft | 469 | | 767 | Reorganize String | Medium | Amazon, Facebook, Google | 470 | | 187 | Repeated DNA Sequences | Medium | Google | 471 | | 93 | Restore IP Addresses | Medium | Microsoft | 472 | | 92 | Reverse Linked List II | Medium | Adobe, Alibaba, Amazon, Facebook, Google, Microsoft | 473 | | 151 | Reverse Words in a String | Medium | Facebook | 474 | | 186 | Reverse Words in a String II | Medium | Amazon, Microsoft | 475 | | 900 | RLE Iterator | Medium | Amazon, Google | 476 | | 61 | Rotate List | Medium | Amazon, Microsoft | 477 | | 74 | Search a 2D Matrix | Medium | Amazon, Facebook, Google, Microsoft | 478 | | 240 | Search a 2D Matrix II | Medium | Amazon, Facebook, Google, Microsoft | 479 | | 702 | Search in a Sorted Array of Unknown Size | Medium | Google | 480 | | 33 | Search in Rotated Sorted Array | Medium | Alibaba, Amazon, Apple, Facebook, Google, Microsoft | 481 | | 81 | Search in Rotated Sorted Array II | Medium | Google | 482 | | 418 | Sentence Screen Fitting | Medium | Google | 483 | | 737 | Sentence Similarity II | Medium | Google | 484 | | 444 | Sequence Reconstruction | Medium | Google | 485 | | 449 | Serialize and Deserialize BST | Medium | Amazon, Facebook, Google, Microsoft | 486 | | 73 | Set Matrix Zeroes | Medium | Amazon, Apple, Facebook, Google, Microsoft | 487 | | 384 | Shuffle an Array | Medium | Amazon, Google, Microsoft | 488 | | 71 | Simplify Path | Medium | Adobe, Amazon, Facebook, Microsoft | 489 | | 540 | Single Element in a Sorted Array | Medium | Amazon, Google | 490 | | 137 | Single Number II | Medium | Amazon, Facebook, Google | 491 | | 260 | Single Number III | Medium | Adobe, Facebook | 492 | | 865 | Smallest Subtree with all the Deepest Nodes | Medium | Facebook | 493 | | 909 | Snakes and Ladders | Medium | Amazon | 494 | | 640 | Solve the Equation | Medium | Amazon | 495 | | 451 | Sort Characters By Frequency | Medium | Amazon, Google, Microsoft | 496 | | 75 | Sort Colors | Medium | Adobe, Amazon, Apple, Facebook, Google, Microsoft | 497 | | 148 | Sort List | Medium | Amazon, Facebook, Google, Microsoft | 498 | | 360 | Sort Transformed Array | Medium | Facebook, Google | 499 | | 311 | Sparse Matrix Multiplication | Medium | Apple | 500 | | 54 | Spiral Matrix | Medium | Adobe, Amazon, Apple, Facebook, Google, Microsoft | 501 | | 59 | Spiral Matrix II | Medium | Amazon, Google, Microsoft | 502 | | 885 | Spiral Matrix III | Medium | Facebook | 503 | | 659 | Split Array into Consecutive Subsequences | Medium | Google | 504 | | 548 | Split Array with Equal Sum | Medium | Facebook | 505 | | 776 | Split BST | Medium | Google | 506 | | 725 | Split Linked List in Parts | Medium | Google | 507 | | 877 | Stone Game | Medium | Google | 508 | | 8 | String to Integer (atoi) | Medium | Apple | 509 | | 247 | Strobogrammatic Number II | Medium | Google | 510 | | 713 | Subarray Product Less Than K | Medium | Akuna Capital | 511 | | 560 | Subarray Sum Equals K | Medium | Facebook, Microsoft | 512 | | 78 | Subsets | Medium | Adobe, Amazon, Apple, Facebook, Google, Microsoft | 513 | | 90 | Subsets II | Medium | Amazon | 514 | | 228 | Summary Ranges | Medium | Amazon, Google, Microsoft | 515 | | 130 | Surrounded Regions | Medium | Amazon, Google | 516 | | 777 | Swap Adjacent in LR String | Medium | Google | 517 | | 24 | Swap Nodes in Pairs | Medium | Adobe, Amazon, Google | 518 | | 494 | Target Sum | Medium | Facebook, Google | 519 | | 621 | Task Scheduler | Medium | Amazon, Apple, Facebook, Google, Microsoft | 520 | | 490 | The Maze | Medium | Microsoft | 521 | | 505 | The Maze II | Medium | Amazon, Google | 522 | | 981 | Time Based Key-Value Store | Medium | Facebook | 523 | | 347 | Top K Frequent Elements | Medium | Facebook, Google, Microsoft | 524 | | 692 | Top K Frequent Words | Medium | Amazon, Apple, Facebook, Google, Microsoft | 525 | | 477 | Total Hamming Distance | Medium | Facebook | 526 | | 120 | Triangle | Medium | Amazon, Microsoft | 527 | | 264 | Ugly Number II | Medium | Google | 528 | | 96 | Unique Binary Search Trees | Medium | Amazon, Google | 529 | | 95 | Unique Binary Search Trees II | Medium | Adobe, Amazon, Google | 530 | | 62 | Unique Paths | Medium | Alibaba, Amazon, Apple, Facebook, Google, Microsoft | 531 | | 63 | Unique Paths II | Medium | Amazon, Facebook, Microsoft | 532 | | 288 | Unique Word Abbreviation | Medium | Google | 533 | | 393 | UTF-8 Validation | Medium | Facebook, Google | 534 | | 678 | Valid Parenthesis String | Medium | Facebook | 535 | | 36 | Valid Sudoku | Medium | Amazon, Apple, Facebook, Google, Microsoft | 536 | | 794 | Valid Tic-Tac-Toe State | Medium | Microsoft | 537 | | 611 | Valid Triangle Number | Medium | Amazon | 538 | | 98 | Validate Binary Search Tree | Medium | Adobe, Amazon, Apple, Facebook, Microsoft | 539 | | 468 | Validate IP Address | Medium | Facebook, Google | 540 | | 987 | Vertical Order Traversal of a Binary Tree | Medium | Adobe, Facebook | 541 | | 286 | Walls and Gates | Medium | Amazon | 542 | | 365 | Water and Jug Problem | Medium | Google | 543 | | 280 | Wiggle Sort | Medium | Google | 544 | | 324 | Wiggle Sort II | Medium | Facebook, Airbnb, Akuna Capital | 545 | | 139 | Word Break | Medium | Adobe, Amazon, Apple, Facebook, Google, Microsoft | 546 | | 192 | Word Frequency | Medium | Adobe, Amazon, Facebook | 547 | | 127 | Word Ladder | Medium | Affirm, Airbnb, Amazon, Apple, Facebook, Google, Microsoft | 548 | | 79 | Word Search | Medium | Amazon, Apple, Facebook, Microsoft | 549 | | 6 | ZigZag Conversion | Medium | Adobe, Amazon, Apple, Facebook, Google | 550 | | 281 | Zigzag Iterator | Medium | Google | 551 | | 48 | Rotate Image | Medium | Facebook | 552 | | 679 | 24 Game | Hard | Google, Microsoft | 553 | | 269 | Alien Dictionary | Hard | Amazon, Google | 554 | | 432 | All Oone Data Structure | Hard | Amazon, Facebook | 555 | | 446 | Arithmetic Slices II - Subsequence | Hard | Alibaba, Facebook | 556 | | 224 | Basic Calculator | Hard | Adobe, Amazon, Facebook, Google, Microsoft | 557 | | 772 | Basic Calculator III | Hard | Amazon, Facebook, Google, Microsoft | 558 | | 770 | Basic Calculator IV | Hard | Google | 559 | | 296 | Best Meeting Point | Hard | Google, Facebook | 560 | | 123 | Best Time to Buy and Sell Stock III | Hard | Amazon, Microsoft | 561 | | 188 | Best Time to Buy and Sell Stock IV | Hard | Amazon, Google | 562 | | 968 | Binary Tree Cameras | Hard | Google | 563 | | 124 | Binary Tree Maximum Path Sum | Hard | Apple | 564 | | 145 | Binary Tree Postorder Traversal | Hard | Amazon | 565 | | 803 | Bricks Falling When Hit | Hard | Google | 566 | | 312 | Burst Balloons | Hard | Amazon, Google | 567 | | 815 | Bus Routes | Hard | Airbnb, Amazon, Google | 568 | | 135 | Candy | Hard | Google | 569 | | 913 | Cat and Mouse | Hard | Google | 570 | | 272 | Closest Binary Search Tree Value II | Hard | Amazon | 571 | | 472 | Concatenated Words | Hard | Amazon | 572 | | 829 | Consecutive Numbers Sum | Hard | Adobe, Airbnb | 573 | | 730 | Count Different Palindromic Subsequences | Hard | Google | 574 | | 315 | Count of Smaller Numbers After Self | Hard | Adobe, Apple | 575 | | 630 | Course Schedule III | Hard | Google | 576 | | 753 | Cracking the Safe | Hard | Amazon, Google | 577 | | 675 | Cut Off Trees for Golf Event | Hard | Amazon | 578 | | 639 | Decode Ways II | Hard | Facebook | 579 | | 185 | Department Top Three Salaries | Hard | Adobe, Amazon, Google | 580 | | 631 | Design Excel Sum Formula | Hard | Amazon | 581 | | 588 | Design In-Memory File System | Hard | Amazon | 582 | | 642 | Design Search Autocomplete System | Hard | Google | 583 | | 115 | Distinct Subsequences | Hard | Google | 584 | | 940 | Distinct Subsequences II | Hard | Google | 585 | | 174 | Dungeon Game | Hard | Amazon | 586 | | 72 | Edit Distance | Hard | Facebook, Adobe, Amazon, Apple, Google, Microsoft | 587 | | 759 | Employee Free Time | Hard | Airbnb, Amazon, Google, Microsoft | 588 | | 471 | Encode String with Shortest Length | Hard | Google | 589 | | 282 | Expression Add Operators | Hard | Google, Apple, Facebook | 590 | | 336 | Facebook - LeetCodePalindrome Pairs 30.7% | Hard | Facebook | 591 | | 579 | Find Cumulative Salary of an Employee | Hard | Amazon | 592 | | 295 | Find Median from Data Stream | Hard | Akuna Capital, Amazon, Apple, Facebook, Google, Microsoft | 593 | | 154 | Find Minimum in Rotated Sorted Array II | Hard | Facebook, Google | 594 | | 564 | Find the Closest Palindrome | Hard | Amazon, Facebook, Microsoft | 595 | | 943 | Find the Shortest Superstring | Hard | Google | 596 | | 41 | First Missing Positive | Hard | Amazon | 597 | | 403 | Frog Jump | Hard | Amazon, Apple, Facebook, Google | 598 | | 843 | Guess the Word | Hard | Airbnb, Amazon, Facebook, Google | 599 | | 381 | Insert Delete GetRandom O(1) - Duplicates allowed | Hard | Affirm, Amazon | 600 | | 57 | Insert Interval | Hard | Amazon, Apple, Facebook, Google, Microsoft | 601 | | 273 | Integer to English Words | Hard | Amazon | 602 | | 97 | Interleaving String | Hard | Amazon, Apple, Microsoft | 603 | | 45 | Jump Game II | Hard | Adobe, Amazon, Apple, Google | 604 | | 683 | K Empty Slots | Hard | Google, Microsoft | 605 | | 854 | K-Similar Strings | Hard | Google | 606 | | 668 | Kth Smallest Number in Multiplication Table | Hard | Google | 607 | | 479 | Largest Palindrome Product | Hard | Apple | 608 | | 84 | Largest Rectangle in Histogram | Hard | Microsoft | 609 | | 460 | LFU Cache | Hard | Amazon | 610 | | 128 | Longest Consecutive Sequence | Hard | Alibaba, Google | 611 | | 329 | Longest Increasing Path in a Matrix | Hard | Facebook | 612 | | 340 | Longest Substring with At Most K Distinct Characters | Hard | Facebook, Google | 613 | | 159 | Longest Substring with At Most Two Distinct | Hard | Facebook | 614 | | 32 | Longest Valid Parentheses | Hard | Amazon | 615 | | 146 | LRU Cache | Hard | Alibaba | 616 | | 827 | Making A Large Island | Hard | Google | 617 | | 768 | Max Chunks To Make Sorted II | Hard | Google | 618 | | 149 | Max Points on a Line | Hard | Adobe, Amazon, Google, Microsoft | 619 | | 363 | Max Sum of Rectangle No Larger Than K | Hard | Google | 620 | | 85 | Maximal Rectangle | Hard | Adobe, Amazon, Google, Microsoft | 621 | | 895 | Maximum Frequency Stack | Hard | Amazon | 622 | | 164 | Maximum Gap | Hard | Amazon | 623 | | 689 | Maximum Sum of 3 Non-Overlapping Subarrays | Hard | Facebook, Google | 624 | | 568 | Maximum Vacation Days | Hard | Facebook, Google, Microsoft | 625 | | 4 | Median of Two Sorted Arrays | Hard | Alibaba, Apple | 626 | | 23 | Merge k Sorted Lists | Hard | Adobe, Alibaba, Amazon, Apple, Facebook, Google, Microsoft | 627 | | 924 | Minimize Malware Spread | Hard | Amazon | 628 | | 774 | Minimize Max Distance to Gas Station | Hard | Google | 629 | | 857 | Minimum Cost to Hire K Workers | Hard | Google | 630 | | 995 | Minimum Number of K Consecutive Bit Flips | Hard | Akuna Capital | 631 | | 871 | Minimum Number of Refueling Stops | Hard | Amazon | 632 | | 727 | Minimum Window Subsequence | Hard | Google | 633 | | 76 | Minimum Window Substring | Hard | Airbnb | 634 | | 51 | N-Queens | Hard | Alibaba, Amazon, Facebook, Microsoft | 635 | | 726 | Number of Atoms | Hard | Adobe | 636 | | 233 | Number of Digit One | Hard | Amazon | 637 | | 711 | Number of Distinct Islands II | Hard | Amazon | 638 | | 305 | Number of Islands II | Hard | Amazon, Google | 639 | | 920 | Number of Music Playlists | Hard | Google | 640 | | 975 | Odd Even Jump | Hard | Google | 641 | | 465 | Optimal Account Balancing | Hard | Google | 642 | | 132 | Palindrome Partitioning II | Hard | Google | 643 | | 736 | Parse Lisp Expression | Hard | Affirm | 644 | | 745 | Prefix and Suffix Search | Hard | Google | 645 | | 793 | Preimage Size of Factorial Zeroes Function | Hard | Amazon | 646 | | 818 | Race Car | Hard | Google | 647 | | 710 | Random Pick with Blacklist | Hard | Amazon, Google | 648 | | 715 | Range Module | Hard | Google | 649 | | 308 | Range Sum Query 2D - Mutable | Hard | Facebook, Google | 650 | | 158 | Read N Characters Given Read4 II - Call multiple | Hard | Facebook | 651 | | 99 | Recover Binary Search Tree | Hard | Facebook, Google | 652 | | 850 | Rectangle Area II | Hard | Google | 653 | | 685 | Redundant Connection II | Hard | Google | 654 | | 10 | Regular Expression Matching | Hard | Alibaba, Amazon, Google | 655 | | 316 | Remove Duplicate Letters | Hard | Microsoft | 656 | | 301 | Remove Invalid Parentheses | Hard | Amazon, Google | 657 | | 25 | Reverse Nodes in k-Group | Hard | Amazon | 658 | | 493 | Reverse Pairs | Hard | Apple, Facebook, Google, Microsoft | 659 | | 489 | Robot Room Cleaner | Hard | Amazon, Google | 660 | | 354 | Russian Doll Envelopes | Hard | Google | 661 | | 87 | Scramble String | Hard | Google | 662 | | 297 | Serialize and Deserialize Binary Tree | Hard | Amazon, Facebook, Google, Microsoft | 663 | | 428 | Serialize and Deserialize N-ary Tree | Hard | Facebook | 664 | | 317 | Shortest Distance from All Buildings | Hard | Amazon | 665 | | 847 | Shortest Path Visiting All Nodes | Hard | Amazon | 666 | | 862 | Shortest Subarray with Sum at Least K | Hard | Facebook | 667 | | 773 | Sliding Puzzle | Hard | Airbnb, Amazon, Google | 668 | | 239 | Sliding Window Maximum | Hard | Apple, Microsoft | 669 | | 480 | Sliding Window Median | Hard | Amazon, Google | 670 | | 632 | Smallest Range | Hard | Facebook, Microsoft | 671 | | 302 | Smallest Rectangle Enclosing Black Pixels | Hard | Google | 672 | | 761 | Special Binary String | Hard | Google | 673 | | 410 | Split Array Largest Sum | Hard | Google | 674 | | 805 | Split Array With Same Average | Hard | Google | 675 | | 936 | Stamping The Sequence | Hard | Google | 676 | | 248 | Strobogrammatic Number III | Hard | Facebook | 677 | | 552 | Student Attendance Record II | Hard | Google | 678 | | 992 | Subarrays with K Different Integers | Hard | Amazon | 679 | | 30 | Substring with Concatenation of All Words | Hard | Adobe, Apple, Facebook, Google | 680 | | 37 | Sudoku Solver | Hard | Amazon | 681 | | 834 | Sum of Distances in Tree | Hard | Google | 682 | | 778 | Swim in Rising Water | Hard | Amazon | 683 | | 591 | Tag Validator | Hard | Google | 684 | | 68 | Text Justification | Hard | Airbnb, Amazon, Facebook, Google, Microsoft | 685 | | 42 | Trapping Rain Water | Hard | Adobe, , Amazon, Apple, Facebook, Google, Microsoft | 686 | | 407 | Trapping Rain Water II | Hard | Apple, Google, Microsoft | 687 | | 262 | Trips and Users | Hard | Adobe | 688 | | 980 | Unique Paths III | Hard | Amazon | 689 | | 65 | Valid Number | Hard | Apple, Facebook, Google, Microsoft | 690 | | 44 | Wildcard Matching | Hard | Adobe, Amazon, Facebook, Google, Microsoft | 691 | | 527 | Word Abbreviation | Hard | Google | 692 | | 140 | Word Break II | Hard | Amazon, Apple, Facebook | 693 | | 126 | Word Ladder II | Hard | Facebook, Google, Microsoft | 694 | | 291 | Word Pattern II | Hard | Facebook | 695 | | 212 | Word Search II | Hard | Airbnb, Amazon, Apple, Facebook, Microsoft | 696 | | 425 | Word Squares | Hard | Google | 697 | | 218 | The Skyline Problem | Hard | Facebook | 698 | --------------------------------------------------------------------------------