Group Anagrams

Group the words that are anagrams of each other (same letters, any order).

Input:

• line 1: n
• next n lines: one word each (lowercase letters)

Output: one group per line, the words of a group separated by spaces. So that there is exactly one correct output:

• inside a group, sort the words alphabetically (keep duplicates);
• sort the groups by comparing them word by word (so the group whose first word is alphabetically smallest comes first).

Constraints: 1 ≤ n ≤ 10⁴, 1 ≤ word length ≤ 100.

Think about it: two words are anagrams exactly when their sorted letters (or their 26 letter counts) are equal — use that as a hash-map key.