CF1325E.Ehab's REAL Number Theory Problem

普及/提高-

通过率：0%

AC君温馨提醒

该题目为【codeforces】题库的题目，您提交的代码将被提交至codeforces进行远程评测，并由ACGO抓取测评结果后进行展示。由于远程测评的测评机由其他平台提供，我们无法保证该服务的稳定性，若提交后无反应，请等待一段时间后再进行重试。

题目描述

You are given an array $a$ of length $n$ that has a special condition: every element in this array has at most 7 divisors. Find the length of the shortest non-empty subsequence of this array product of whose elements is a perfect square.

A sequence $a$ is a subsequence of an array $b$ if $a$ can be obtained from $b$ by deletion of several (possibly, zero or all) elements.

输入格式

The first line contains an integer $n$ ( $1 \le n \le 10^5$ ) — the length of $a$ .

The second line contains $n$ integers $a_1$ , $a_2$ , $\ldots$ , $a_{n}$ ( $1 \le a_i \le 10^6$ ) — the elements of the array $a$ .

输出格式

Output the length of the shortest non-empty subsequence of $a$ product of whose elements is a perfect square. If there are several shortest subsequences, you can find any of them. If there's no such subsequence, print "-1".

输入输出样例

输入#1
```
3
1 4 6
```
输出#1
```
1
```
输入#2
```
4
2 3 6 6
```
输出#2
```
2
```
输入#3
```
3
6 15 10
```
输出#3
```
3
```
输入#4
```
4
2 3 5 7
```
输出#4
```
-1
```

说明/提示

In the first sample, you can choose a subsequence $[1]$ .

In the second sample, you can choose a subsequence $[6, 6]$ .

In the third sample, you can choose a subsequence $[6, 15, 10]$ .

In the fourth sample, there is no such subsequence.

首页