961.n

Description

In a array A of size 2N, there are N+1 unique elements, and exactly one of these elements is repeated N times.

Return the element repeated N times.


在大小为 2N 的数组 A 中有 N+1 个不同的元素,其中有一个元素重复了 N 次。

返回重复了 N 次的那个元素。

题目链接:https://leetcode.com/problems/n-repeated-element-in-size-2n-array

Difficulty: easy

Example 1:

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

Example 2:

Input: [2,1,2,5,3,2]
Output: 2

Example 3:

Input: [5,1,5,2,5,3,5,4]
Output: 5

Note:

  • 4 <= A.length <= 10000
  • 0 <= A[i] < 10000
  • A.length is even

分析

  • updating

参考代码

class Solution:
def repeatedNTimes(self, A):
    D=set()
    for a in A:
        if(a not in D):
            D.add(a)
        else:
            return a
    return