human
I found an interesting problem on https://leetcode.com/problems/number-of-equivalent-domino-pairs/:
Given a list of dominoes, dominoes[i] = [a, b] is equivalent to dominoes[j] = [c, d] if and only if either (a==c and b==d), or (a==d and b==c) - that is, one domino can be rotated to be equal to another domino.
Return the number of pairs (i, j) for which 0 <= i < j < dominoes.length, and dominoes[i] is equivalent to dominoes[j].
 
Example 1:
Input: dominoes = [[1,2],[2,1],[3,4],[5,6]]
Output: 1

 
Constraints:

1 <= dominoes.length <= 40000
1 <= dominoes[i][j] <= 9

I tried it in Python, but could not do it. Can you solve it?

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Can you provide a the Python program you requested?
assistant
#Here is the Python program you requested.

class Solution:
    def numEquivDominoPairs(self, dominoes: List[List[int]]) -> int:
        c = collections.Counter()
        for i in dominoes:
            c[tuple(sorted(i))] += 1
            
        return sum(math.comb(i, 2) for i in c.values())