https://acs.jxnu.edu.cn/problem/NOIOPJENGLISH19
1000ms 65536K
Given a sequence of N numbers, find a number A that the count of A in the sequence is at least two.
给出一列有n个数,找到数字a,a的数量在序列里倒数第二
First line: one positive integer N (N <= 1000).
Second line: N positive integers (<= 1000000).
第一行:一个正整数表示n
第二行:n个正整数
One integer A.
一个数表示a
8 2 4 2 1 5 3 9 6
2