Score : 300 points
We will call a string obtained by arranging the characters contained in a string a in some order, an anagram of a.
For example, greenbin
is an anagram of beginner
. As seen here, when the same character occurs multiple times, that character must be used that number of times.
Given are N strings s_1, s_2, \ldots, s_N. Each of these strings has a length of 10 and consists of lowercase English characters. Additionally, all of these strings are distinct. Find the number of pairs of integers i, j (1 \leq i < j \leq N) such that s_i is an anagram of s_j.
Input is given from Standard Input in the following format:
N s_1 s_2 : s_N
Print the number of pairs of integers i, j (1 \leq i < j \leq N) such that s_i is an anagram of s_j.
3 acornistnt peanutbomb constraint
1
s_1 = acornistnt
is an anagram of s_3 = constraint
. There are no other pairs i, j such that s_i is an anagram of s_j, so the answer is 1.
2 oneplustwo ninemodsix
0
If there is no pair i, j such that s_i is an anagram of s_j, print 0.
5 abaaaaaaaa oneplustwo aaaaaaaaba twoplusone aaaabaaaaa
4
Note that the answer may not fit into a 32-bit integer type, though we cannot put such a case here.