Algorithm in LeetCode —— Linked List

Aug 18

Tips for Linked Lists:

Cleverly introduce a dummy head node. This can make traversal and processing logic more uniform.
Use recursion flexibly. By defining the right recursive conditions, recursion can solve certain problems elegantly. However, note that some problems should not be solved recursively, because excessive recursion depth can lead to timeouts and stack overflows.
Reverse a range within a linked list. Problem 92.
Find the middle node of a linked list. Problem 876. Find the nth node from the end of a linked list. Problem 19. The answer can be obtained with just one traversal.
Merge K sorted linked lists. Problems 21 and 23.
Classify linked list nodes. Problems 86 and 328.
Sort a linked list with required time complexity O(n * log n) and space complexity O(1). There is only one approach: merge sort, using top-down merging. Problem 148.
Determine whether a linked list has a cycle; if it does, output the index of the intersection point of the cycle. Determine whether two linked lists intersect; if they do, output the intersection point. Problems 141, 142, and 160.

Title	Solution	Difficulty	Time	Space	Favorites
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)