| 146 | LRU Cache | — | Medium | Hash TableLinked ListDesign | 45% | |
| 155 | Min Stack | — | Medium | StackDesign | 56% | |
| 173 | Binary Search Tree Iteratorread | — | Medium | StackTreeDesign | 75% | |
| 208 | Implement Trie (Prefix Tree) | — | Medium | Hash TableStringDesign | 68% | |
| 211 | Design Add and Search Words Data Structure | — | Medium | StringDepth-First SearchDesign | 47% | |
| 225 | Implement Stack using Queues | — | Easy | StackDesignQueue | 67% | |
| 232 | Implement Queue using Stacks | — | Easy | StackDesignQueue | 68% | |
| 271 | Encode and Decode Strings | — | Medium | ArrayStringDesign | 49% | |
| 284 | Peeking Iteratorread | — | Medium | ArrayDesignIterator | 60% | |
| 295 | Find Median from Data Stream | — | Hard | Two PointersDesignSorting | 53% | |
| 297 | Serialize and Deserialize Binary Tree | — | Hard | StringTreeDepth-First Search | 59% | |
| 303 | Range Sum Query - Immutable | — | Easy | ArrayDesignPrefix Sum | 68% | |
| 304 | Range Sum Query 2D - Immutable | — | Medium | ArrayDesignMatrix | 56% | |
| 307 | Range Sum Query - Mutable | — | Medium | ArrayDesignBinary Indexed Tree | 42% | |
| 341 | Flatten Nested List Iteratorread | — | Medium | StackTreeDepth-First Search | 65% | |
| 352 | Data Stream as Disjoint Intervalsread | — | Hard | Binary SearchDesignOrdered Set | 59% | |
| 355 | Design Twitter | — | Medium | Hash TableLinked ListDesign | 42% | |
| 380 | Insert Delete GetRandom O(1)read | — | Medium | ArrayHash TableMath | 55% | |
| 381 | Insert Delete GetRandom O(1) - Duplicates allowedread | — | Hard | ArrayHash TableMath | 36% | |
| 384 | Shuffle an Arrayread | — | Medium | ArrayMathDesign | 59% | |
| 432 | All O`one Data Structureread | — | Hard | Hash TableLinked ListDesign | 44% | |
| 449 | Serialize and Deserialize BSTread | — | Medium | StringTreeDepth-First Search | 59% | |
| 460 | LFU Cache | — | Hard | Hash TableLinked ListDesign | 46% | |
| 535 | Encode and Decode TinyURLread | — | Medium | Hash TableStringDesign | 86% | |
| 622 | Design Circular Queue | — | Medium | ArrayLinked ListDesign | 52% | |
| 641 | Design Circular Deque | — | Medium | ArrayLinked ListDesign | 64% | |
| 676 | Implement Magic Dictionaryread | — | Medium | Hash TableStringDepth-First Search | 57% | |
| 677 | Map Sum Pairs | — | Medium | Hash TableStringDesign | 57% | |
| 703 | Kth Largest Element in a Stream | — | Easy | TreeDesignBinary Search Tree | 60% | |
| 705 | Design HashSet | — | Easy | ArrayHash TableLinked List | 67% | |
| 706 | Design HashMap | — | Easy | ArrayHash TableLinked List | 66% | |
| 707 | Design Linked List | — | Medium | Linked ListDesign | 29% | |
| 715 | Range Module | — | Hard | DesignSegment TreeOrdered Set | 44% | |
| 729 | My Calendar Iread | — | Medium | ArrayBinary SearchDesign | 58% | |
| 731 | My Calendar II | — | Medium | ArrayBinary SearchDesign | 62% | |
| 732 | My Calendar III | — | Hard | Binary SearchDesignSegment Tree | 71% | |
| 745 | Prefix and Suffix Search | — | Hard | ArrayHash TableString | 40% | |
| 855 | Exam Room | — | Medium | DesignHeap (Priority Queue)Ordered Set | 43% | |
| 895 | Maximum Frequency Stack | — | Hard | Hash TableStackDesign | 66% | |
| 900 | RLE Iterator | — | Medium | ArrayDesignCounting | 59% | |
| 901 | Online Stock Span | — | Medium | StackDesignMonotonic Stack | 67% | |
| 911 | Online Election | — | Medium | ArrayHash TableBinary Search | 52% | |
| 919 | Complete Binary Tree Inserterread | — | Medium | TreeBreadth-First SearchDesign | 65% | |
| 933 | Number of Recent Calls | — | Easy | DesignQueueData Stream | 77% | |
| 981 | Time Based Key-Value Store | — | Medium | Hash TableStringBinary Search | 49% | |
| 1032 | Stream of Charactersread | — | Hard | ArrayStringDesign | 51% | |
| 1146 | Snapshot Array | — | Medium | ArrayHash TableBinary Search | 37% | |
| 1157 | Online Majority Element In Subarray | — | Hard | ArrayBinary SearchDesign | 39% | |
| 1172 | Dinner Plate Stacks | — | Hard | Hash TableStackDesign | 33% | |
| 1206 | Design Skiplist | — | Hard | Linked ListDesign | 58% | |