Challenge: Find the Minimum Platforms Required For a Station

Problem statement

Implement a function that returns the minimum number of platforms that are required for the train so that none of them waits.

Input

Two lists which represent arrival and departure times of trains that stop

Output

Minimum number of platforms required

Sample input

Arrival Time	Departure Time
9:00	9:10
9:40	12:00
9:50	11:20
11:00	11:30
15:00	19:00
18:00	20:00

arrival= [900, 940, 950, 1100, 1500, 1800]
departure = [910, 1200, 1120, 1130, 1900, 2000]

Sample output

result = 3