hdu 1008 Elevator

#include <iostream>using namespace std;int main(){    int N,i,sum,a[1000];    a[0]=0;    while(cin>>N,N)    {        sum=0;        for(i=1; i<=N; i++)            cin>>a[i];        for(i=1; i<=N;i++)        {            if(a[i]>a[i-1])                sum=sum+(a[i]-a[i-1])*6;            else                sum=sum+(a[i-1]-a[i])*4;        }        cout<<sum+N*5<<endl;    }    return 0;}