Question

There are n processes in a queue. Each process has name_i and time_i. The round-robin scheduling handles the processes in order. A round-robin scheduler gives each process a quantum (a time slot) and interrupts the process if it is not completed by then. The process is resumed and moved to the end of the queue, then the scheduler handles the next process in the queue.

For example, we have the following queue with the quantum of 100ms.

A(150) - B(80) - C(200) - D(200)

First, process A is handled for 100ms, then the process is moved to the end of the queue with the remaining time (50ms).

B(80) - C(200) - D(200) - A(50)

Next, process B is handled for 80ms. The process is completed with the time stamp of 180ms and removed from the queue.

C(200) - D(200) - A(50)

Your task is to write a program which simulates the round-robin scheduling.

Input

n q
name₁ time₁
name₂ time₂
...
name_n time_n

In the first line the number of processes n and the quantum q are given separated by a single space.

In the following n lines, names and times for the n processes are given. name_i and time_i are separated by a single space.

Output

For each process, prints its name and the time the process finished in order.

Constraints

• 1 ≤ n ≤ 100000
• 1 ≤ q ≤ 1000
• 1 ≤ time_i ≤ 50000
• 1 ≤ length of name_i ≤ 10
• 1 ≤ Sum of time_i ≤ 1000000

Sample Input 1

5 100
p1 150
p2 80
p3 200
p4 350
p5 20

Sample Output 1

p2 180
p5 400
p1 450
p3 550
p4 800

Answer 1

The source is mention below in python3 language.

Source Code:

n,quantum=map(int,input().split())
l=[]
ll=[]
p=0
t=0
output_process=[]
output_time=[]
for i in range(n):
pro,ti=input().split()
l.append(int(ti))

for i in range(n):
ll.append(i+1)
print(ll)
state=n
i=0
while i<state:
if l[i]>quantum:
l.append(l[i]-quantum)
ll.append(ll[p])
p=p+1
t=t+quantum
if l[i]<=quantum:
output_process.append(ll[p])
t=t+l[i]
output_time.append(t)
p=p+1
state=len(l)
i=i+1
for i in range(n):
print('p'+str(output_process[i]),end=" ")
print(output_time[i])

Explaination:

The parameters that are used are explained below

ll is a list used to store the process number

l is a list used to store the time needed to complete the process.

t is time used so far to complete the process

output_process is a list that is used to store the processes in order of completion

output_time is a list that is used to store the time at which the process is completed.

p is a pointer that points to list ll