preface
Recently, some friends asked me why I haven’t updated my article. I have been scanning LeetCode for nearly two months now and then in my spare time, and I have accumulated a lot of questions. Therefore, I plan to classify the hundreds of questions I have done recently and summarize them. The code for all topics is available at github.com/halfrost/Le… Each problem has test cases and test code.
Linked List of Tips:
- Cleverly construct virtual headers. Can make traversal processing logic more uniform.
- Be flexible with recursion. Construct recursion condition, use recursion can clever solution problem. Note, however, that you should not use recursion for some problems, because too deep recursion can cause timeouts and stack overflows.
- List interval reverse order. The 92th.
- Linked lists look for intermediate nodes. The 876th. The linked list looks for the NTH to last node. 19 items. It only takes one walk to get the answer.
- Merge K ordered linked lists. Problem 21. Problem 23.
- Linked list categorization. Problem 86. Problem 328.
- Linked list sorting requires O(n * log n) time complexity and O(1) space complexity. There’s only one way to do it, merge sort, top down merge. The 148th.
- Determine whether the linked list has a ring, if there is a ring, output the index of the intersection of the ring; Check if two lists have intersections, if so, output the intersections. Problem 141. Problem 142. Problem 160.
| Title | Solution | Difficulty | Time | Space | collection |
|---|---|---|---|---|---|
| 2. Add Two Numbers | Go | Medium | O(n) | O(1) | |
| 19. Remove Nth Node From End of List | Go | Medium | O(n) | O(1) | |
| 21. Merge Two Sorted Lists | Go | Easy | O(log n) | O(1) | |
| 23. Merge k Sorted Lists | Go | Hard | O(log n) | O(1) | ❤ ️ |
| 24. Swap Nodes in Pairs | Go | Medium | O(n) | O(1) | |
| 25. Reverse Nodes in k-Group | Go | Hard | O(log n) | O(1) | ❤ ️ |
| 61. Rotate List | Go | Medium | O(n) | O(1) | |
| 82. Remove Duplicates from Sorted List II | Go | Medium | O(n) | O(1) | |
| 83. Remove Duplicates from Sorted List | Go | Easy | O(n) | O(1) | |
| 86. Partition List | Go | Medium | O(n) | O(1) | ❤ ️ |
| 92. Reverse Linked List II | Go | Medium | O(n) | O(1) | ❤ ️ |
| 109. Convert Sorted List to Binary Search Tree | Go | Medium | O(log n) | O(n) | |
| 141. Linked List Cycle | Go | Easy | O(n) | O(1) | ❤ ️ |
| 142. Linked List Cycle II | Go | Medium | O(n) | O(1) | ❤ ️ |
| 143. Reorder List | Go | Medium | O(n) | O(1) | ❤ ️ |
| 147. Insertion Sort List | Go | Medium | O(n) | O(1) | |
| 148. Sort List | Go | Medium | O(log n) | O(n) | ❤ ️ |
| 160. Intersection of Two Linked Lists | Go | Easy | O(n) | O(1) | ❤ ️ |
| 203. Remove Linked List Elements | Go | Easy | O(n) | O(1) | |
| 206. Reverse Linked List | Go | Easy | O(n) | O(1) | |
| 234. Palindrome Linked List | Go | Easy | O(n) | O(1) | |
| 237. Delete Node in a Linked List | Go | Easy | O(n) | O(1) | |
| 328. Odd Even Linked List | Go | Medium | O(n) | O(1) | |
| 445. Add Two Numbers II | Go | Medium | O(n) | O(n) | |
| 725. Split Linked List in Parts | Go | Medium | O(n) | O(1) | |
| 817. Linked List Components | Go | Medium | O(n) | O(1) | |
| 707. Design Linked List | Go | Easy | O(n) | O(1) | |
| 876. Middle of the Linked List | Go | Easy | O(n) | O(1) | ❤ ️ |
| 1019. Next Greater Node In Linked List | Go | Medium | O(n) | O(1) |