LeetCode 49 ·
Medium
Group Anagrams
Group the strings that are anagrams of each other.
Try it
Step through the core mechanic. The simulator below runs the hash map shape this problem is built on.
Walk the pattern
No dedicated step-through for this one yet. The shape is Hash map — its pattern page has the interactive walkthrough, the reference implementation, and a five-problem progression that this problem sits inside.
The approach
Key each word by its sorted letters (or its 26-count tuple) and append into a hash map of key→list. The map values are the groups.
| Aspect | Value |
|---|---|
| Pattern | Hash map |
| Recognise it by | Bucket strings by a canonical key. |
| Time complexity | O(n·k log k) |
| Space complexity | O(n·k) |
| Difficulty | Medium |
Who asks it
Companies known to ask this problem, from public LeetCode company-tag aggregations. A signal of where to expect it, not a guarantee.