silam
diff --git a/‎scheduling/highest_response_ratio_next.py‎
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+"""
+Highest response ratio next (HRRN) scheduling is a non-preemptive discipline.
+It was developed as modification of shortest job next or shortest job first (SJN or SJF)
+to mitigate the problem of process starvation.
+https://en.wikipedia.org/wiki/Highest_response_ratio_next
+"""
+from statistics import mean
+
+import numpy as np
+
+
+def calculate_turn_around_time(
+    process_name: list, arrival_time: list, burst_time: list, no_of_process: int
+) -> list:
+    """
+    Calculate the turn around time of each processes
+
+    Return: The turn around time time for each process.
+    >>> calculate_turn_around_time(["A", "B", "C"], [3, 5, 8], [2, 4, 6], 3)
+    [2, 4, 7]
+    >>> calculate_turn_around_time(["A", "B", "C"], [0, 2, 4], [3, 5, 7], 3)
+    [3, 6, 11]
+    """
+
+    current_time = 0
+    # Number of processes finished
+    finished_process_count = 0
+    # Displays the finished process.
+    # If it is 0, the performance is completed if it is 1, before the performance.
+    finished_process = [0] * no_of_process
+    # List to include calculation results
+    turn_around_time = [0] * no_of_process
+
+    # Sort by arrival time.
+    burst_time = [burst_time[i] for i in np.argsort(arrival_time)]
+    process_name = [process_name[i] for i in np.argsort(arrival_time)]
+    arrival_time.sort()
+
+    while no_of_process > finished_process_count:
+
+        """
+        If the current time is less than the arrival time of
+        the process that arrives first among the processes that have not been performed,
+        change the current time.
+        """
+        i = 0
+        while finished_process[i] == 1:
+            i += 1
+        if current_time < arrival_time[i]:
+            current_time = arrival_time[i]
+
+        response_ratio = 0
+        # Index showing the location of the process being performed
+        loc = 0
+        # Saves the current response ratio.
+        temp = 0
+        for i in range(0, no_of_process):
+            if finished_process[i] == 0 and arrival_time[i] <= current_time:
+                temp = (burst_time[i] + (current_time - arrival_time[i])) / burst_time[
+                    i
+                ]
+            if response_ratio < temp:
+                response_ratio = temp
+                loc = i
+
+        # Calculate the turn around time
+        turn_around_time[loc] = current_time + burst_time[loc] - arrival_time[loc]
+        current_time += burst_time[loc]
+        # Indicates that the process has been performed.
+        finished_process[loc] = 1
+        # Increase finished_process_count by 1
+        finished_process_count += 1
+
+    return turn_around_time
+
+
+def calculate_waiting_time(
+    process_name: list, turn_around_time: list, burst_time: list, no_of_process: int
+) -> list:
+    """
+    Calculate the waiting time of each processes.
+
+    Return: The waiting time for each process.
+    >>> calculate_waiting_time(["A", "B", "C"], [2, 4, 7], [2, 4, 6], 3)
+    [0, 0, 1]
+    >>> calculate_waiting_time(["A", "B", "C"], [3, 6, 11], [3, 5, 7], 3)
+    [0, 1, 4]
+    """
+
+    waiting_time = [0] * no_of_process
+    for i in range(0, no_of_process):
+        waiting_time[i] = turn_around_time[i] - burst_time[i]
+    return waiting_time
+
+
+if __name__ == "__main__":
+
+    no_of_process = 5
+    process_name = ["A", "B", "C", "D", "E"]
+    arrival_time = [1, 2, 3, 4, 5]
+    burst_time = [1, 2, 3, 4, 5]
+
+    turn_around_time = calculate_turn_around_time(
+        process_name, arrival_time, burst_time, no_of_process
+    )
+    waiting_time = calculate_waiting_time(
+        process_name, turn_around_time, burst_time, no_of_process
+    )
+
+    print("Process name \tArrival time \tBurst time \tTurn around time \tWaiting time")
+    for i in range(0, no_of_process):
+        print(
+            f"{process_name[i]}\t\t{arrival_time[i]}\t\t{burst_time[i]}\t\t"
+            f"{turn_around_time[i]}\t\t\t{waiting_time[i]}"
+        )
+
+    print(f"average waiting time : {mean(waiting_time):.5f}")
+    print(f"average turn around time : {mean(turn_around_time):.5f}")