BZOJ 4488/4052 gcd

//By SiriusRen
#include <cstdio>
#include <algorithm>
using namespace std;
typedef long long ll;
int cases,n,top,temp;
ll xx,ans;
struct Node{int id;ll gcd;}jy[33],al[33];
ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
int main(){
        scanf("%d",&n),ans=top=0;
        for(int i=1;i<=n;i++){
            scanf("%lld",&xx),temp=0;
            jy[++top].gcd=0,jy[top].id=i;
            for(int j=1;j<=top;j++)jy[j].gcd=gcd(jy[j].gcd,xx);
            for(int j=1;j<=top;j++)if(jy[j].gcd!=jy[j-1].gcd)
                ans=max(ans,jy[j].gcd*(i+1-jy[j].id)),jy[++temp]=jy[j];
            top=temp;
        }
        printf("%lld\n",ans);
}