594. Longest Harmonious Subsequence

https://leetcode.com/problems/longest-harmonious-subsequence/

Longest Harmonious Subsequence - LeetCode

450ms

import collections

class Solution:
    def findLHS(self, nums: List[int]) -> int:
        if len(nums) < 1:
            return 0
        if len(set(nums)) == 1:
            return 0
        
        uniq_nums = set(nums)
        memo = collections.defaultdict(int)
        
        res = 0
        for idx, num in enumerate(nums):
            if num-1 in uniq_nums:
                _key = '{}-{}'.format(num-1, num)
                memo[_key] += 1
                res = max(res, memo[_key])
            if num+1 in uniq_nums:
                _key = '{}-{}'.format(num, num+1)
                memo[_key] += 1
                res = max(res, memo[_key])
            
        return res

 

simplify

 

300ms

class Solution:
    def findLHS(self, A):
        count = collections.Counter(A)
        ans = 0
        for x in count:
            if x+1 in count:
                ans = max(ans, count[x] + count[x+1])
        return ans