题解 | #数组中重复的数字#

from re import S
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param numbers int整型一维数组 
# @return int整型
#
class Solution:
    def duplicate(self , numbers: List[int]) -> int:
        s = len(numbers)
        if s <= 1 :
            return -1
        nums = set()
        for num in numbers:
            if num in nums:
                return num
            nums.add(num)
        return -1
        # write code here