TimeforTickets.py (using Queue)

from collections import deque
class Solution:
    def timeRequiredToBuy(self, tickets: List[int], k: int) -> int:
        
        # Let's maintain a Queue, which stores both Index(Person Number) & Num. of tickets Person Wants
        queue = deque([ [0,tickets[0]] ])
        # Pushing Values into Queue,, such that Index is also Retained
        for i in range(1,len(tickets)): # TC : O(N)
            queue.append( [i, tickets[i]] )

        time_taken = 0 # Final Answer

        while queue: # Worst-Case TC : O(N)
            front_person = queue.popleft() # Taking out 1st Person from Queue # TC : O(1)
            
            if front_person[1] >= 1: # If he wants some Tickets
                front_person[1] -= 1 # Decreasing Tickets by 1
                time_taken += 1 # Increasing Time by 1

                queue.append( [front_person[0], front_person[1]] ) # Again Putting the same Person at the End of Line(Queue)
            
            # If Front Person has same Index as K & Don't Require any Tickets,, then Break
            if front_person[0] == k and front_person[1] == 0: 
                break

        return time_taken