[mypy] Add/fix type annotations for scheduling algorithms (#4074)

* Fix mypy errors for scheduling/first_come_first_served
* Fix mypy errors for scheduling/round_robin.py
* Fix mypy errors for scheduling/shortest_job_first.py
* Fix isort errors

scheduling/first_come_first_served.py

@@ -2,10 +2,10 @@
 # In this Algorithm we just care about the order that the processes arrived
 # without carring about their duration time
 # https://en.wikipedia.org/wiki/Scheduling_(computing)#First_come,_first_served
-from __future__ import annotations
+from typing import List
 
 
-def calculate_waiting_times(duration_times: list[int]) -> list[int]:
+def calculate_waiting_times(duration_times: List[int]) -> List[int]:
     """
     This function calculates the waiting time of some processes that have a
     specified duration time.
@@ -24,8 +24,8 @@ def calculate_waiting_times(duration_times: list[int]) -> list[int]:
 
 
 def calculate_turnaround_times(
-    duration_times: list[int], waiting_times: list[int]
+    duration_times: List[int], waiting_times: List[int]
-) -> list[int]:
+) -> List[int]:
     """
     This function calculates the turnaround time of some processes.
         Return: The time difference between the completion time and the
@@ -44,7 +44,7 @@ def calculate_turnaround_times(
     ]
 
 
-def calculate_average_turnaround_time(turnaround_times: list[int]) -> float:
+def calculate_average_turnaround_time(turnaround_times: List[int]) -> float:
     """
     This function calculates the average of the turnaround times
         Return: The average of the turnaround times.
@@ -58,7 +58,7 @@ def calculate_average_turnaround_time(turnaround_times: list[int]) -> float:
     return sum(turnaround_times) / len(turnaround_times)
 
 
-def calculate_average_waiting_time(waiting_times: list[int]) -> float:
+def calculate_average_waiting_time(waiting_times: List[int]) -> float:
     """
     This function calculates the average of the waiting times
         Return: The average of the waiting times.

scheduling/round_robin.py

@@ -3,12 +3,11 @@ Round Robin is a scheduling algorithm.
 In Round Robin each process is assigned a fixed time slot in a cyclic way.
 https://en.wikipedia.org/wiki/Round-robin_scheduling
 """
-from __future__ import annotations
-
 from statistics import mean
+from typing import List
 
 
-def calculate_waiting_times(burst_times: list[int]) -> list[int]:
+def calculate_waiting_times(burst_times: List[int]) -> List[int]:
     """
     Calculate the waiting times of a list of processes that have a specified duration.
 
@@ -41,8 +40,8 @@ def calculate_waiting_times(burst_times: list[int]) -> list[int]:
 
 
 def calculate_turn_around_times(
-    burst_times: list[int], waiting_times: list[int]
+    burst_times: List[int], waiting_times: List[int]
-) -> list[int]:
+) -> List[int]:
     """
     >>> calculate_turn_around_times([1, 2, 3, 4], [0, 1, 3])
     [1, 3, 6]

scheduling/shortest_job_first.py

@@ -3,17 +3,17 @@ Shortest job remaining first
 Please note arrival time and burst
 Please use spaces to separate times entered.
 """
-from __future__ import annotations
+from typing import List
 
 import pandas as pd
 
 
 def calculate_waitingtime(
-    arrival_time: list[int], burst_time: list[int], no_of_processes: int
+    arrival_time: List[int], burst_time: List[int], no_of_processes: int
-) -> list[int]:
+) -> List[int]:
     """
     Calculate the waiting time of each processes
-    Return: list of waiting times.
+    Return: List of waiting times.
     >>> calculate_waitingtime([1,2,3,4],[3,3,5,1],4)
     [0, 3, 5, 0]
     >>> calculate_waitingtime([1,2,3],[2,5,1],3)
@@ -72,8 +72,8 @@ def calculate_waitingtime(
 
 
 def calculate_turnaroundtime(
-    burst_time: list[int], no_of_processes: int, waiting_time: list[int]
+    burst_time: List[int], no_of_processes: int, waiting_time: List[int]
-) -> list[int]:
+) -> List[int]:
     """
     Calculate the turn around time of each Processes
     Return: list of turn around times.
@@ -91,8 +91,8 @@ def calculate_turnaroundtime(
 
 
 def calculate_average_times(
-    waiting_time: list[int], turn_around_time: list[int], no_of_processes: int
+    waiting_time: List[int], turn_around_time: List[int], no_of_processes: int
-):
+) -> None:
     """
     This function calculates the average of the waiting & turnaround times
     Prints: Average Waiting time & Average Turn Around Time