Problem URL: Divide array into equal pairs

We can use a hashmap to store the frequency of each element in the array. Then we can iterate over the array and check if the frequency of the current element is even or not. If it is even, we can divide it by 2 and add it to the result. If it is odd, we can return false.

class Solution:
    def divideArray(self, nums: List[int]) -> bool:
        count = collections.Counter(nums)
        for num in count.values():
            if num % 2 != 0:
                return False
        return True

Time complexity: O(n)
Space complexity: O(n)