4420: Average of Two Numbers
内存限制：128 MB
时间限制：1 S
标准输入输出
题目类型：传统
评测方式：Special Judge
上传者：
提交：46
通过：16
题目描述
Given a list of n different numbers, which number in this list can be represented as an average of any two other numbers in the same list?
输入格式
There are multiple test cases.
The first line of each test case is an integer n, where 3 ≤ n ≤ 1000. The second line contains n different positive integers seperated by spaces, denoting the list of numbers. The numbers are in ascending order and every number in this list is less than 109.
输出格式
For each test case, output the number of numbers in this list which can be represented as an average of any two other numbers in the same list.
输入样例 复制
3
1 2 3
6
3 4 6 7 8 9输出样例 复制
1
3数据范围与提示
In the first case, 2 can be represented by (1 + 3) / 2.
In the second case, 6 can be represented by (3 + 9) / 2, 7 can be represented by (6 + 8) / 2, 8 can be represented by (7 + 9) / 2.