Remove Duplicates from Sorted List II
A medium-tier problem at 50% community acceptance, tagged with Linked List, Two Pointers. Reported in interviews at Tencent and 6 others.
Remove Duplicates from Sorted List II hits your assessment and you freeze. You know you need to track duplicates in a linked list, but the logic for skipping entire groups of duplicates trips you up. This medium-difficulty problem appears frequently at Microsoft, Google, Amazon, Apple, and Bloomberg. Nearly 50 percent of candidates submit a working solution, but the other half struggle with pointer manipulation and edge cases. If you haven't drilled the two-pointer pattern on lists, StealthCoder runs invisibly during your assessment and surfaces a clean solution when you blank on the grouping logic.
Companies that ask "Remove Duplicates from Sorted List II"
Remove Duplicates from Sorted List II is the kind of problem that decides whether you pass. StealthCoder reads the problem on screen and surfaces a working solution in under 2 seconds. Invisible to screen share. The proctor sees nothing. Made by an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too.
Get StealthCoderThe trick is understanding that you're not just removing individual duplicate nodes, you're removing all nodes in a duplicate group. Most candidates start by comparing adjacent nodes and deleting one, but that leaves duplicates behind. The real pattern uses two pointers and a dummy node to skip entire groups at once. When you see duplicates, you fast-forward past all of them in one pass, then reconnect. The setup is friction: you need a sentinel node at the head to handle the case where the first few nodes get deleted. Edge cases like all nodes being duplicates or no duplicates at all trip up candidates who don't test rigorously. StealthCoder is the hedge if you walk into the OA having done one practice run and the variant throws you off.
Pattern tags
You know the problem.
Make sure you actually pass it.
Remove Duplicates from Sorted List II recycles across companies for a reason. It's medium-tier, and most candidates blank under the timer. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds. Made by an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Remove Duplicates from Sorted List II interview FAQ
Is this problem actually asked at FAANG?+
Yes. It appears in reports from Google, Microsoft, Amazon, Apple, and Bloomberg. It's not the most common linked list problem, but it shows up enough that you should know the two-pointer pattern cold before your OA.
What's the core trick I'm missing?+
You need to skip entire duplicate groups, not just individual nodes. Use a dummy node, a previous pointer, and a current pointer. When you detect duplicates, fast-forward current past all of them, then reconnect previous.next to current.next in one jump.
How is this different from Remove Duplicates from Sorted List?+
The original version keeps one copy of each duplicate. This version removes all duplicates entirely. That changes the whole algorithm. You're not modifying nodes, you're skipping groups and rewiring the list.
What edge cases break most solutions?+
All nodes are duplicates (return an empty list). Duplicates at the head (why the dummy node matters). No duplicates at all (should return the original list unchanged). Single node and two identical nodes test your null checks.
Is this tagged with the right topics?+
Yes. It's pure Linked List and Two Pointers. The algorithm is O(n) time, one pass with two pointers. No sorting, no extra data structures. Just pointer logic and careful case handling.
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