2025-08-02 15:59:52 +0000 UTC

Check If N and Its Double Exist

Code

class Solution:
    def checkIfExist(self, arr: List[int]) -> bool:
        enc = set()
        for num in arr:
            if num == 0 and 0 in enc:
                return True
            if num % 2 == 0 and num // 2 in enc:
                return True
            if num * 2 in enc:
                return True
            enc.add(num)
        return False