Group Anagrams

Group the words that are anagrams of each other (they use exactly the same letters). Inside a group sort the words alphabetically (repeated words stay), and sort the groups by their first word. Return the list of groups.

Examples

Example 1

Input:

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

Output:

[['ate', 'eat', 'tea'], ['bat'], ['nat', 'tan']]

Example 2

Input:

group_anagrams(['a'])

Output:

[['a']]

Constraints

• 0 <= len(words) <= 10**5
• Each word has at most 12 lower-case letters.