5307: Geometrical problem

内存限制:256 MB 时间限制:2 S
题面:传统 评测方式:文本比较 上传者:
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题目描述

D. Geometrical problem
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output
Polycarp loves geometric progressions − he collects them. However, as such progressions occur very rarely, he also loves the sequences of numbers where it is enough to delete a single element to get a geometric progression.
In this task we shall define geometric progressions as finite sequences of numbers a1,a2,...,ak, where ai=c·bi-1 for some real numbers c and b. For example, the sequences [2, -4, 8], [0, 0, 0, 0], [199] are geometric progressions and [0, 1, 2, 3] is not.
Recently Polycarp has found a sequence and he can't classify it. Help him to do it. Determine whether it is a geometric progression. If it is not, check if it can become a geometric progression if an element is deleted from it.
Input
The first line contains an integer n (1≤n≤105) − the number of elements in the given sequence. The second line contains the given sequence. The numbers are space-separated. All the elements of the given sequence are integers and their absolute value does not exceed 104.
Output
Print 0, if the given sequence is a geometric progression. Otherwise, check if it is possible to make the sequence a geometric progression by deleting a single element. If it is possible, print 1. If it is impossible, print 2.
Examples
Input
4
3 6 12 24
Output
0
Input
4
-8 -16 24 -32
Output
1
Input
4
0 1 2 3
Output
2

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