LeetCode 49 Group Anagrams gives you an array of strings. Your task is to group the anagrams together. Anagrams are words with the same letters rearranged.
For example, if strs = ["eat","tea","tan","ate","nat","bat"], you'd return [["eat","tea","ate"],["tan","nat"],["bat"]]. Notice "eat", "tea", and "ate" all have the same letters.
Before moving on, think: how can you quickly tell if two strings are anagrams? And how can you use that to group them efficiently?
Constraints: , string length up to .