Time limit 2000/4000/4000/4000 ms. Memory limit 65000/65000/65000/65000 Kb.
Question by Ibrahim Mesecan.
Elevator
The university has a new building. For the economic
difficulties, the elevator just carries people
from ground floor to the upper floors. Thus people
walk down when returning.
The people are grouped according to the floor
numbers they want to go. Then, until the
elevator is full. The elevator
climbs up till the last person's destination floor.
Then, it returns back to the ground floor. To give
a fast service, the elevator starts lifting people
who wants to go to the lowest floors.
Question:
Write a program that is going to read the people
and elevator information, then your program will
calculate the total number of floors that the elevator
has traveled.
Input specification
You will be given two integers in the first line:
the number of floors (n) and the capacity of the elevator
(cap: the number of people it can carry at once).
Then in the following n lines you will be given
integers which are between 0 and 1000. n is an integer
between 1 and 30000 and cap is between 1 and 1000.
Output specification
Show one integer: the total number of floors
that the elevator has climbed.
Sample Input I
5 6
4
3
8
2
0
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Sample Output I
9
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Explanation:
There five floors and elevator can carry at most
6 people. And, there are 4 people waiting for the
first floor, 3 people waiting for the second floor, etc.
- On the first run, the elevator takes 4 people for
the first floor and 2 people for the second floor.
And it leaves them to their floors: climbed up to
the second floor.
- On the second run, it takes 1 person for the second
floor and 5 people for the third floor: climbed up to
the third floor; and the total number of floors
climbed is 5.
- On the last run, it takes 3 people for the third
floor and 2 people for the fourth floor: climbed
up to the 4th floor; and the total is 9.
Для отправки решений необходимо выполнить вход.
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