307235: CF1325E. Ehab's REAL Number Theory Problem
Memory Limit:256 MB
Time Limit:3 S
Judge Style:Text Compare
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Description
Ehab's REAL Number Theory Problem
题意翻译
给一些数,每个的因数个数不超过 $7$,求最少选出多少个,使得乘积为完全平方。无解输出 $-1$。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.输入输出格式
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
输入样例 #1
3
1 4 6
输出样例 #1
1
输入样例 #2
4
2 3 6 6
输出样例 #2
2
输入样例 #3
3
6 15 10
输出样例 #3
3
输入样例 #4
4
2 3 5 7
输出样例 #4
-1