X of a Kind in a Deck of Cards — LeetCode 914 Python Solution

The problem

You are given an integer array deck where deck[i] represents the number written on the ith card. Partition the cards into one or more groups such that: Each group has exactly x cards where x > 1, and All the cards in one group have the same integer written on them.

Example

Input

deck = [1,2,3,4,4,3,2,1]

Output

true

Explanation

Possible partition [1,1],[2,2],[3,3],[4,4].

Python solution

class Solution:
    def hasGroupsSizeX(self, deck: List[int]) -> bool:
        cnt = Counter(deck)
        return reduce(gcd, cnt.values()) >= 2

Complexity

Pattern: Math and Number Theory

Find the closed form, the invariant, or the modular identity — and skip the loop entirely. LeetCode 914. X of a Kind in a Deck of Cards is filed here because LeetCode tags it Math and Number Theory, which is the vocabulary this hub collects.

The math and number theory guide has the Python template for the pattern and the 485 LeetCode problems that use it.

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