Remove Duplicates from Sorted List II
Given the head of a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.
Return the linked list after removing all duplicates.
Example 1
Input
head = [1,2,3,3,4,4,5]
Output
[1,2,5]
Explanation
3 and 4 appear more than once, so all nodes containing those values are removed.
Example 2
Input
head = [1,1,1,2,3]
Output
[2,3]
Explanation
All occurrences of 1 are duplicates, so they are completely removed. The remaining list is [2,3].
Constraints
Hints:
Hint 1
Use a dummy node before the head so that duplicates at the beginning can be removed easily.
Hint 2
When consecutive nodes have the same value, skip all nodes with that value instead of keeping one occurrence.
Author & Technical Reviewer
Technically reviewed by: ExamAdda Technical Review Team
Technical Reviewers, ExamAdda
Software engineers at ExamAdda who check every article's definitions, complexity claims and code examples before and after publishing.
Published
Aug 18, 2026
Last updated
Aug 19, 2026
Content Verification Methodology
Definitions and complexity claims were checked against authoritative computer-science references. Code examples were compiled and tested with standard, boundary and edge-case inputs.
Expected Output