Parco_Love_gcd

传送门

出题人说正解为RMQ，鄙人实在太蒟蒻了，不会呀只能暴力……

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define re register
const int N=1e6+;
const int mod=1e9+;
void read(int &a)
{
    a=;
    int d=;
    char ch;
    while(ch=getchar(),ch>''||ch<'')
        if(ch=='-')
            d=-;
    a=ch-'';
    while(ch=getchar(),ch>=''&&ch<='')
        a=a*+ch-'';
    a*=d;
}
void write(int x)
{
    if(x<)
        putchar(),x=-x;
    if(x>)
        write(x/);
    putchar(x%+'');
}
int a[N];
int GCD(int a,int b)
{
    return b==?a:GCD(b,a%b);
}
int main()
{
    int n;
    read(n);
    ll ans=,gcd;
    read(a[]);
    gcd=a[];
    for(re int i=;i<n;i++)
        read(a[i]),gcd=GCD(gcd,a[i]);
    for(re int i=;i<n;i++)
    {
        int now=a[i];
        for(re int j=i;j<n;j++)
        {
            if(now==gcd)
            {
                ans=(ans+(n-j)*gcd)%mod;
                break;
            }
            now=GCD(now,a[j]);
            ans+=now;
            ans%=mod;
        }
    }
    write(ans);
    return ;
}