Problem Description
Do you know what is called ``Coprime Sequence''? That is a sequence consists of n positive
integers, and the GCD (Greatest Common Divisor) of them is equal to 1.
``Coprime Sequence'' is easy to find because of its restriction. But we can try to maximize the GCD of these integers by removing exactly one integer. Now given a sequence, please maximize the GCD of its elements.
``Coprime Sequence'' is easy to find because of its restriction. But we can try to maximize the GCD of these integers by removing exactly one integer. Now given a sequence, please maximize the GCD of its elements.
Input
The first line of the input contains an integer T(1≤T≤10),
denoting the number of test cases.
In each test case, there is an integer n(3≤n≤100000) in the first line, denoting the number of integers in the sequence.
Then the following line consists of n integers a1,a2,...,an(1≤ai≤109), denoting the elements in the sequence.
In each test case, there is an integer n(3≤n≤100000) in the first line, denoting the number of integers in the sequence.
Then the following line consists of n integers a1,a2,...,an(1≤ai≤109), denoting the elements in the sequence.
Output
For each test case, print a single line containing a single integer, denoting the maximum GCD.
Sample Input
3 3 1 1 1 5 2 2 2 3 2 4 1 2 4 8
Sample Output
1 2 2
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
int a[100009];
int main()
{
int T;
scanf("%d",&T);
while(T--)
{
int n;
scanf("%d",&n);
for(int i=0;i<n;i++)
scanf("%d",&a[i]);
int flag=0,k=a[0],x,p=a[0];
a[0]=0;
for(int i=1;i<n;i++)
{
x=__gcd(k,a[i]);
if(x<k)
{
a[flag]=p;
p=a[i];
flag=i;
a[i]=0;
k=x;
}
}
int q=0;
for(int i=0;i<n;i++)
{
if(a[i]&&!q)
{
q=1;
k=a[i];
}
else
{
k=__gcd(k,a[i]);
}
}
printf("%d\n",k);
}
return 0;
}