51nod_1179_計算N個數之間兩兩之間GCD的最大值
阿新 • • 發佈:2019-02-12
#include<iostream>
#include<cstdio>
using namespace std;
const int maxs = 1e6 + 10;
int D[maxs];
int main()
{
int n;
cin >> n;
long long x,themax = 0;
for (int i = 0;i < n;i++)
{
scanf("%lld", &x);
D[x]++;
if (x > themax)
{
themax = x;
}
}
int ans = -1;
for (int i = themax;i > 0;i--)
{
int sum = 0;
for (int j = i;j <= themax&&sum<2;j += i)
{
sum += D[j];
}if (sum == 2)
{
ans = i;
break;
}
}
cout << ans << endl;
return 0;
}