Add round_robin scheduling algorithm

scheduling/round_robin.py

@@ -0,0 +1,65 @@
+"""
+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 statistics import mean
+from typing import List
+
+
+def calculate_waiting_times(burst_times: List[int]) -> List[int]:
+    """
+    Calculate the waiting times of a list of processes that have a specified duration.
+
+    Return: The waiting time for each process.
+    >>> calculate_waiting_times([10, 5, 8])
+    [13, 10, 13]
+    >>> calculate_waiting_times([4, 6, 3, 1])
+    [5, 8, 9, 6]
+    >>> calculate_waiting_times([12, 2, 10])
+    [12, 2, 12]
+    """
+    quantum = 2
+    rem_burst_times = list(burst_times)
+    waiting_times = [0] * len(burst_times)
+    t = 0
+    while 1:
+        done = True
+        for i, burst_time in enumerate(burst_times):
+            if rem_burst_times[i] > 0:
+                done = False
+                if rem_burst_times[i] > quantum:
+                    t += quantum
+                    rem_burst_times[i] -= quantum
+                else:
+                    t += rem_burst_times[i]
+                    waiting_times[i] = t - burst_times[i]
+                    rem_burst_times[i] = 0
+        if done is True:
+            return waiting_times
+
+
+def calculate_turn_around_times(
+    burst_times: List[int], waiting_times: List[int]
+) -> List[int]:
+    """
+    >>> calculate_turn_around_times([1, 2, 3, 4], [0, 1, 3])
+    [1, 3, 6]
+    >>> calculate_turn_around_times([10, 3, 7], [10, 6, 11])
+    [20, 9, 18]
+    """
+    return [burst + waiting for burst, waiting in zip(burst_times, waiting_times)]
+
+
+if __name__ == "__main__":
+    burst_times = [3, 5, 7]
+    waiting_times = calculate_waiting_times(burst_times)
+    turn_around_times = calculate_turn_around_times(burst_times, waiting_times)
+    print("Process ID \tBurst Time \tWaiting Time \tTurnaround Time")
+    for i, burst_time in enumerate(burst_times):
+        print(
+            f"  {i + 1}\t\t  {burst_time}\t\t  {waiting_times[i]}\t\t  "
+            f"{turn_around_times[i]}"
+        )
+    print(f"\nAverage waiting time = {mean(waiting_times):.5f}")
+    print(f"Average turn around time = {mean(turn_around_times):.5f}")