5/24 每日一題(檢查列表中元素是否重複)

 Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct.

 

Example 1:

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

Example 2:

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

Example 3:

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

 

Constraints:

• 1 <= nums.length <= 105
• -109 <= nums[i] <= 109

class Solution:

    def containsDuplicate(self, nums: List[int]) -> bool:

        #把元素放入集合中檢查是否in裡面

        nums_set=set()

        for i in nums:

            if i in nums_set:

                return True

            nums_set.add(i)

        return False