Repeated numbers in the array of "Sword Finger Offer"

Repeated numbers in the array of "Sword Finger Offer"

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Time is hurried, although I have never met, but I met Yusi, it is really a great fate, thank you for your visit!

• Problem :
  All numbers in an array of length n are in the range of 0 to n-1. Some numbers in the array are repeated, but I don't know how many numbers are repeated. I don’t know how many times each number is repeated. Please find the first repeated number in the array. For example, if the input length is 7 array [2,3,1,0,2,5,3], then the corresponding output is the first repeated number 2. Return -1 if there is no repeated number.
• Example :

示例 1 :
输入：[2,3,1,0,2,5,3]
返回值：2

• Code 1:

class Solution:
    def duplicate(self , numbers ):
        temp = 0
        d = {
    
    }
        for i in range(len(numbers)):
            d[numbers[i]] = d.get(numbers[i],0) + 1
            if d[numbers[i]] == 2:
                return numbers[i]
        return -1

• Algorithm description:
  Create a dictionary, traverse the elements in the array one by one, store the number of elements in the dictionary, and return the current element when the number of elements exceeds 2.