Minimum-number-of-taxis

This code is solution to a problem at code wars

Description

You work at a taxi central.

People contact you to order a taxi. They inform you of the time they want to be picked up and dropped off.

A taxi is available to handle a new customer 1 time unit after it has dropped off a previous customer.

What is the minimum number of taxis you need to service all requests?

Constraints:

• Let N be the number of customer requests:
  • N is an integer in the range [1, 100k]
• All times will be integers in range [1, 10k]
• Let PU be the time of pickup and DO be the time of dropoff
  • Then for each request: PU < DO
• The input list is NOT sorted.

Examples:

# Two customers, overlapping schedule. Two taxis needed.
# First customer wants to be picked up 1 and dropped off 4.
# Second customer wants to be picked up 2 and dropped off 6.
requests = [(1, 4), (2, 6)]
min_num_taxis(requests) # => 2

# Two customers, no overlap in schedule. Only one taxi needed.
# First customer wants to be picked up 1 and dropped off 4.
# Second customer wants to be picked up 5 and dropped off 9.
requests = [(1, 4), (5, 9)]
min_num_taxis(requests) # => 1