--- title: Linked List type: docs --- # Linked List ![](https://img.halfrost.com/Leetcode/Linked_List.png) - 巧妙的构造虚拟头结点。可以使遍历处理逻辑更加统一。 - 灵活使用递归。构造递归条件，使用递归可以巧妙的解题。不过需要注意有些题目不能使用递归，因为递归深度太深会导致超时和栈溢出。 - 链表区间逆序。第 92 题。 - 链表寻找中间节点。第 876 题。链表寻找倒数第 n 个节点。第 19 题。只需要一次遍历就可以得到答案。 - 合并 K 个有序链表。第 21 题，第 23 题。 - 链表归类。第 86 题，第 328 题。 - 链表排序，时间复杂度要求 O(n * log n)，空间复杂度 O(1)。只有一种做法，归并排序，至顶向下归并。第 148 题。 - 判断链表是否存在环，如果有环，输出环的交叉点的下标；判断 2 个链表是否有交叉点，如果有交叉点，输出交叉点。第 141 题，第 142 题，第 160 题。 | Title | Solution | Difficulty | Time | Space |收藏| | ----- | :--------: | :----------: | :----: | :-----: | :-----: | |2. Add Two Numbers | [Go]({{< relref "/ChapterFour/0002.Add-Two-Numbers.md" >}})| Medium | O(n)| O(1)|| |19. Remove Nth Node From End of List | [Go]({{< relref "/ChapterFour/0019.Remove-Nth-Node-From-End-of-List.md" >}})| Medium | O(n)| O(1)|| |21. Merge Two Sorted Lists | [Go]({{< relref "/ChapterFour/0021.Merge-Two-Sorted-Lists.md" >}})| Easy | O(log n)| O(1)|| |23. Merge k Sorted Lists| [Go]({{< relref "/ChapterFour/0023.Merge-k-Sorted-Lists.md" >}})| Hard | O(log n)| O(1)|❤️| |24. Swap Nodes in Pairs | [Go]({{< relref "/ChapterFour/0024.Swap-Nodes-in-Pairs.md" >}})| Medium | O(n)| O(1)|| |25. Reverse Nodes in k-Group | [Go]({{< relref "/ChapterFour/0025.Reverse-Nodes-in-k-Group.md" >}})| Hard | O(log n)| O(1)|❤️| |61. Rotate List | [Go]({{< relref "/ChapterFour/0061.Rotate-List.md" >}})| Medium | O(n)| O(1)|| |82. Remove Duplicates from Sorted List II | [Go]({{< relref "/ChapterFour/0082.Remove-Duplicates-from-Sorted-List-II.md" >}})| Medium | O(n)| O(1)|| |83. Remove Duplicates from Sorted List | [Go]({{< relref "/ChapterFour/0083.Remove-Duplicates-from-Sorted-List.md" >}})| Easy | O(n)| O(1)|| |86. Partition List | [Go]({{< relref "/ChapterFour/0086.Partition-List.md" >}})| Medium | O(n)| O(1)|❤️| |92. Reverse Linked List II | [Go]({{< relref "/ChapterFour/0092.Reverse-Linked-List-II.md" >}})| Medium | O(n)| O(1)|❤️| |109. Convert Sorted List to Binary Search Tree | [Go]({{< relref "/ChapterFour/0109.Convert-Sorted-List-to-Binary-Search-Tree.md" >}})| Medium | O(log n)| O(n)|| |141. Linked List Cycle | [Go]({{< relref "/ChapterFour/0141.Linked-List-Cycle.md" >}})| Easy | O(n)| O(1)|❤️| |142. Linked List Cycle II | [Go]({{< relref "/ChapterFour/0142.Linked-List-Cycle-II.md" >}})| Medium | O(n)| O(1)|❤️| |143. Reorder List | [Go]({{< relref "/ChapterFour/0143.Reorder-List.md" >}})| Medium | O(n)| O(1)|❤️| |147. Insertion Sort List | [Go]({{< relref "/ChapterFour/0147.Insertion-Sort-List.md" >}})| Medium | O(n)| O(1)|❤️| |148. Sort List | [Go]({{< relref "/ChapterFour/0148.Sort-List.md" >}})| Medium | O(n log n)| O(n)|❤️| |160. Intersection of Two Linked Lists | [Go]({{< relref "/ChapterFour/0160.Intersection-of-Two-Linked-Lists.md" >}})| Easy | O(n)| O(1)|❤️| |203. Remove Linked List Elements | [Go]({{< relref "/ChapterFour/0203.Remove-Linked-List-Elements.md" >}})| Easy | O(n)| O(1)|| |206. Reverse Linked List | [Go]({{< relref "/ChapterFour/0206.Reverse-Linked-List.md" >}})| Easy | O(n)| O(1)|| |234. Palindrome Linked List | [Go]({{< relref "/ChapterFour/0234.Palindrome-Linked-List.md" >}})| Easy | O(n)| O(1)|| |237. Delete Node in a Linked List | [Go]({{< relref "/ChapterFour/0237.Delete-Node-in-a-Linked-List.md" >}})| Easy | O(n)| O(1)|| |328. Odd Even Linked List | [Go]({{< relref "/ChapterFour/0328.Odd-Even-Linked-List.md" >}})| Medium | O(n)| O(1)|| |445. Add Two Numbers II | [Go]({{< relref "/ChapterFour/0445.Add-Two-Numbers-II.md" >}})| Medium | O(n)| O(n)|| |725. Split Linked List in Parts | [Go]({{< relref "/ChapterFour/0725.Split-Linked-List-in-Parts.md" >}})| Medium | O(n)| O(1)|| |817. Linked List Components | [Go]({{< relref "/ChapterFour/0817.Linked-List-Components.md" >}})| Medium | O(n)| O(1)|| |707. Design Linked List | [Go]({{< relref "/ChapterFour/0707.Design-Linked-List.md" >}})| Easy | O(n)| O(1)|| |876. Middle of the Linked List | [Go]({{< relref "/ChapterFour/0876.Middle-of-the-Linked-List.md" >}})| Easy | O(n)| O(1)|❤️| |1019. Next Greater Node In Linked List | [Go]({{< relref "/ChapterFour/1019.Next-Greater-Node-In-Linked-List.md" >}})| Medium | O(n)| O(1)|| |---------------------------------------------|---------------------------------|--------------------------|-----------------------|-----------|--------|