杭电ACM HDU 1008

#include <cstdio>
int main(){
    int n;
    int pre,f;
    int sum;
    while(scanf("%d",&n)&&n){
        sum=n*5;
        pre=0;
        for(int i=0;i<n;i++){
            scanf("%d",&f);
            if(f>pre)
                sum+=(f-pre)*6;
            else
                sum+=(pre-f)*4;
            pre=f;
        }
        printf("%d\n",sum);
    }
}