import sys

def sjf_preemptive(processes, n):
    remaining_time = [bt for _, _, bt in processes]
    complete = 0
    t = 0
    minm = sys.maxsize
    shortest = 0
    finish_time = 0
    check = False
    waiting_time = [0] * n
    turnaround_time = [0] * n

    while complete != n:
        for j in range(n):
            if processes[j][1] <= t and remaining_time[j] < minm and remaining_time[j] > 0:
                minm = remaining_time[j]
                shortest = j
                check = True

        if not check:
            t += 1
            continue

        remaining_time[shortest] -= 1
        minm = remaining_time[shortest] if remaining_time[shortest] > 0 else sys.maxsize

        if remaining_time[shortest] == 0:
            complete += 1
            check = False
            finish_time = t + 1
            waiting_time[shortest] = finish_time - processes[shortest][2] - processes[shortest][1]

            if waiting_time[shortest] < 0:
                waiting_time[shortest] = 0

        t += 1

    for i in range(n):
        turnaround_time[i] = processes[i][2] + waiting_time[i]

    print("\nSJF (Preemptive) Scheduling:")
    for i, process in enumerate(processes):
        print(f"Process {process[0]}: Waiting Time = {waiting_time[i]}, Turnaround Time = {turnaround_time[i]}")

# Input: Process ID, Arrival Time, Burst Time
processes = [[1, 0, 8], [2, 1, 4], [3, 2, 9], [4, 3, 5]]
sjf_preemptive(processes, len(processes))