Group Anagrams

Difficulty: Hard · Topic: Arrays & strings

Given a list of strings strs, group the anagrams together. Return a list of groups; sort each group ascending, and the groups may be in any order. Two words are anagrams iff their sorted characters match — use that as a dictionary key.

Examples

group_anagrams(["eat","tea","tan","ate","nat","bat"])
→ [["ate","eat","tea"],["nat","tan"],["bat"]]

group_anagrams(["a"])
→ [["a"]]

Target complexity: time O(n·k log k), space O(n·k)

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