hdu1008Elevator

http://acm.hdu.edu.cn/showproblem.php?pid=1008

#include <iostream>
using namespace std;
int main(int argc, char *argv[])
{
    int n;
    int a;
    while(cin>>n)
    {   
if(n>0)
        {
        int i=0;
        int s=0;
        while(n--)
        {
            cin>>a;
            if(i<a)
            {
                s+=6*(a-i);
                s+=5;
                i=a;
            }
            else
            {
                s+=4*(i-a);
                s+=5;
                i=a;
            }
           
        }
            cout<<s<<endl;
    }
    else break;
    }
        return 0;
}