Minimum number of platforms needed

min_platforms.py

# Problem statement is here -> https://www.geeksforgeeks.org/minimum-number-platforms-required-railwaybus-station/

# Assuming the schedule is already sorted!

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

# Uncomment these two lines if schedules are not already sorted
#arrival.sort()
#departure.sort()

arr, dep = 1, 0
platforms = 1

while arr < len(arrival):
  if arrival[arr] <= departure[dep]: platforms +=1
  arr+=1
  dep+=1

if platforms != 1: totalplatforms = platforms-1

print(totalplatforms)

# Time complexity if schedules are sorted -> O(n)