Group Anagrams
Problem
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 <= 1040 <= strs[i].length <= 100strs[i]consists of lowercase English letters.
Solution
- HashMap
- m = len(strs)
- n = avg len(s)
- Time: O(m * n)
- Space: O(m * n) (worst case)
class Solution(object):
def groupAnagrams(self, strs):
"""
:type strs: List[str]
:rtype: List[List[str]]
"""
res = defaultdict(list)
for s in strs:
count = [0] * 26 # a ... z
for c in s:
count[ord(c) - ord('a')] += 1
res[tuple(count)].append(s)
return res.values()