杭电 OJ 1008 Elevator

#include <iostream>
#include <vector>
using namespace std;

int main()
{
	int N;
	while (cin >> N&&N != 0)
	{
		int sum = N * 5;
		vector<int> vec(N);
		for (int i = 0; i < N; i++)
			cin >> vec[i];
		sum += vec[0] * 6;
		for (int i = 1; i < N; i++)
		{
			int sub = vec[i] - vec[i - 1];
			if (sub > 0)
				sum += sub * 6;
			else
				sum += (-sub) * 4;
		}
		cout << sum << endl;
	}
	return 0;
}

简单数学题