PAT 甲级 1008 Elevator（25）

The highest building in our city has only one elevator. A request list is made up with N positive numbers. The numbers denote at which floors the elevator will stop, in specified order. It costs 6 seconds to move the elevator up one floor, and 4 seconds to move down one floor. The elevator will stay for 5 seconds at each stop.

For a given request list, you are to compute the total time spent to fulfill the requests on the list. The elevator is on the 0th floor at the beginning and does not have to return to the ground floor when the requests are fulfilled.

Input Specification:

Each input file contains one test case. Each case contains a positive integer N, followed by N positive numbers. All the numbers in the input are less than 100.

Output Specification:

For each test case, print the total time on a single line.

Sample Input:

3 2 3 1

Sample Output:

41

Experiential Summing-up

这道题过于简单，实在没什么可说的。

需要注意的是，当电梯到达最后一层时也是需要停留5s的。

Accepted Code 

#include<bits/stdc++.h>
using namespace std;
int n, sum;
int a[1000];

int main()
{
    a[0] = 0;
    cin >> n;
    for(int i = 1; i <= n; i ++)
    {
        int c;
        cin >> a[i];
        c = a[i] - a[i-1];
        if(c > 0) sum += c*6+5;
        else sum += -c*4+5;
    }
    cout << sum;
    return 0;
}