Find All Lonely Numbers in the Array

You are given an integer array nums. A number x is lonely when it appears only once, and no adjacent numbers (i.e. x + 1 and x - 1) appear in the array.

Return all lonely numbers in nums. You may return the answer in any order.

Example 1:

Input: nums = [10,6,5,8]
Output: [10,8]
Explanation:

• 10 is a lonely number since it appears exactly once and 9 and 11 does not appear in nums.
• 8 is a lonely number since it appears exactly once and 7 and 9 does not appear in nums.
• 5 is not a lonely number since 6 appears in nums and vice versa. Hence, the lonely numbers in nums are [10, 8]. Note that [8, 10] may also be returned.

Example 2:

Input: nums = [1,3,5,3]
Output: [1,5]
Explanation:

• 1 is a lonely number since it appears exactly once and 0 and 2 does not appear in nums.
• 5 is a lonely number since it appears exactly once and 4 and 6 does not appear in nums.
• 3 is not a lonely number since it appears twice. Hence, the lonely numbers in nums are [1, 5]. Note that [5, 1] may also be returned.

Constraints:

• 1 <= nums.length <= 105
• 0 <= nums[i] <= 106

SOLUTION:

from collections import Counter

class Solution:
    def findLonely(self, nums: List[int]) -> List[int]:
        numctr = Counter(nums)
        op = []
        for num in nums:
            if numctr[num] == 1 and num - 1 not in numctr and num + 1 not in numctr:
                op.append(num)
        return op