LC 0217 [E] Contains Duplicate - ALawliet/algorithms GitHub Wiki

class Solution:
    def containsDuplicate(self, nums: List[int]) -> bool:
        # O(n), O(n)
        num_to_freq = defaultdict(int)
        
        for x in nums:
            if num_to_freq[x] > 0:
                return True
            num_to_freq[x] = num_to_freq[x] + 1
            
        return False

    def containsDuplicate(self, nums: List[int]) -> bool:
        # O(n), O(n)
        counter = Counter(nums)
        num_is_dupe = map(lambda freq: freq > 1, counter.values())
        return any(num_is_dupe)

class Solution:
    def containsDuplicate(self, nums: List[int]) -> bool:
        s = set() 

        for x in nums:
            if x in s:
                return True
            s.add(x)
        
        return False