Number of Equivalent Domino Pairs Problem

Number of Equivalent Domino Pairs Problem — ExecCode Easy DSA Practice

Solve the Number of Equivalent Domino Pairs problem on ExecCode. Free online easy DSA practice in Arrays - Logic Building. Write and run code in Java, C++, Python — no signup required to run.

Problem description

Description You are 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. Your task is to compute the required answer and return the number of pairs (i, j) for which 0 <= i < j < dominoes.length , and dominoes[i] is equivalent to dominoes[j].

Examples

Input {"dominoes": [[1, 2], [2, 1], [3, 4], [5, 6]]}; Output 1. Input {"dominoes": [[1, 2], [1, 2], [1, 1], [1, 2], [2, 2]]}; Output 3

Constraints

1 <= dominoes.length <= 4 * 10^4 dominoes[i].length == 2 1 <= dominoes[i][j] <= 9

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