# Python3 implementation for Priority Scheduling with
# Different Arrival Time priority scheduling
"""1. sort the processes according to arrival time
   2. if arrival time is same the acc to priority
   3. apply fcfs """
  
totalprocess = 5
proc = []
for i in range(5):
    l = []
    for j in range(4):
        l.append(0)
    proc.append(l)
 
# Using FCFS Algorithm to find Waiting time
def get_wt_time( wt):
 
    # declaring service array that stores
    # cumulative burst time
    service = [0] * 5
 
    # Initialising initial elements
    # of the arrays
    service[0] = 0
    wt[0] = 0
 
    for i in range(1, totalprocess):
        service[i] = proc[i - 1][1] + service[i - 1]
        wt[i] = service[i] - proc[i][0] + 1
 
        # If waiting time is negative,
        # change it o zero
        if(wt[i] < 0) :    
            wt[i] = 0
         
def get_tat_time(tat, wt):
 
    # Filling turnaroundtime array
    for i in range(totalprocess):
        tat[i] = proc[i][1] + wt[i]
 
def findgc():
     
    # Declare waiting time and
    # turnaround time array
    wt = [0] * 5
    tat = [0] * 5
 
    wavg = 0
    tavg = 0
 
    # Function call to find waiting time array
    get_wt_time(wt)
     
    # Function call to find turnaround time
    get_tat_time(tat, wt)
 
    stime = [0] * 5
    ctime = [0] * 5
    stime[0] = 1
    ctime[0] = stime[0] + tat[0]
     
    # calculating starting and ending time
    for i in range(1, totalprocess):
        stime[i] = ctime[i - 1]
        ctime[i] = stime[i] + tat[i] - wt[i]
 
    print("Process_no\tStart_time\tComplete_time",
               "\tTurn_Around_Time\tWaiting_Time")
 
    # display the process details
    for i in range(totalprocess):
        wavg += wt[i]
        tavg += tat[i]
         
        print(proc[i][3], "\t\t", stime[i],
                         "\t\t", end = " ")
        print(ctime[i], "\t\t", tat[i], "\t\t\t", wt[i])
 
 
    # display the average waiting time
    # and average turn around time
    print("Average waiting time is : ", end = " ")
    print(wavg / totalprocess)
    print("average turnaround time : " , end = " ")
    print(tavg / totalprocess)
 
# Driver code
if __name__ =="__main__":
    arrivaltime = [1, 2, 3, 4, 5]
    bursttime = [3, 5, 1, 7, 4]
    priority = [3, 4, 1, 7, 8]
     
    for i in range(totalprocess):
 
        proc[i][0] = arrivaltime[i]
        proc[i][1] = bursttime[i]
        proc[i][2] = priority[i]
        proc[i][3] = i + 1
     
    # Using inbuilt sort function
    proc = sorted (proc, key = lambda x:x[2])
    proc = sorted (proc)
     
    # Calling function findgc for
    # finding Gantt Chart
    findgc()
 
# This code is contributed by
# Shubham Singh(SHUBHAMSINGH10)