49. Group Anagrams

Description

Given an array of strings strs, group the anagrams together. You can return the answer in any order.

An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once.

Example 1:

Input: strs = ["eat","tea","tan","ate","nat","bat"]
Output: [["bat"],["nat","tan"],["ate","eat","tea"]]

Example 2:

Input: strs = [""]
Output: [[""]]

Example 3:

Input: strs = ["a"]
Output: [["a"]]

Constraints:

1 <= strs.length <= 10⁴
0 <= strs[i].length <= 100
strs[i] consists of lowercase English letters.

Solution

group-anagrams.py

class Solution:
    def groupAnagrams(self, strs: List[str]) -> List[List[str]]:
        mp = defaultdict(list)

        for word in strs:
            cnt = [0] * 26

            for char in word:
                cnt[ord(char) - ord("a")] += 1

            mp[tuple(cnt)].append(word)

        return mp.values()