217. Contains Duplicate

Given an array of integers, find if the array contains any duplicates.

Your function should return true if any value appears at least twice in the array, and it should return false if every element is distinct.

Example 1:

1 2	Input: [1,2,3,1] Output: true

Example 2:

1 2	Input: [1,2,3,4] Output: false

Example 3:

1 2	Input: [1,1,1,3,3,4,3,2,4,2] Output: true

直接比對加入集合前個數或加入看過集合比對都可以

class Solution(object):
    def containsDuplicate(self, nums):
        return len(nums) != len(set(nums))
        
class Solution:
    def containsDuplicate(self, nums: List[int]) -> bool:
        seen= set()
        for n in nums:
            if n in seen:
                return True
            else:
                seen.add(n)
        return False

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