pat甲级1008 Elevator （简单数学）

#include<iostream>
using namespace std;
int main() {
	int n,k,now=0,sum=0;
	cin >> n;
	while (n--) {
		cin >> k;
		if (k > now)	sum +=(k-now)* 6;
		if (k < now)	sum += (now-k)*4;
		sum += 5;
		now = k;
	}
	cout << sum << endl;
	return 0;
}