Divide Array Into Equal Pairs — LeetCode 2206 Python Solution

The problem

You are given an integer array nums consisting of 2 * n integers. You need to divide nums into n pairs such that: Each element belongs to exactly one pair.

Example

Input

nums = [3,2,3,2,2,2]

Output

true

Explanation

There are 6 elements in nums, so they should be divided into 6 / 2 = 3 pairs.

Python solution

class Solution:
    def divideArray(self, nums: List[int]) -> bool:
        cnt = Counter(nums)
        return all(v % 2 == 0 for v in cnt.values())

Complexity

Pattern: Bit Manipulation

Use XOR, masks and the low-bit trick to replace whole data structures with an integer. LeetCode 2206. Divide Array Into Equal Pairs is filed here because LeetCode tags it Bit Manipulation, which is the vocabulary this hub collects.

The bit manipulation guide has the Python template for the pattern and the 194 LeetCode problems that use it.

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