594. 最长和谐子序列

from collections import Counter
from typing import List


class Solution:
    def findLHS(self, nums: List[int]) -> int:
        counter = Counter(nums)

        keys, ans = sorted(counter.keys()), 0
        for a, b in zip(keys[:-1], keys[1:]):
            if b - a == 1:
                ans = max(ans, counter.get(a) + counter.get(b))
        return ans