import pdb
import heapq as h
import sys
# HEAP
# Insert O(log n)
# Delete O(log n)
# Search O(n)
# Building a Heap O(n)

def getMinGates(landingTimes, takeOffTimes, maxWaitTime, initialPlanes):
	intervals = []

	for x in range(0,max(len(landingTimes), len(takeOffTimes))):
		if x >= len(landingTimes):
			intervals.append([0, takeOffTimes[x]])

		if x >= len(takeOffTimes):
			intervals.append([maxWaitTime + landingTimes[x], sys.maxint])

		intervals.append([maxWaitTime + landingTimes[x], takeOffTimes[x]])


	return meetingRooms2(intervals)


def meetingRooms2(intervals=[[0,0]]):
	if (intervals == None or len(intervals) == 0):
		return 0
	# start 0, end 1
	intervals.sort(key=lambda list: list[0])
	minHeap = []
	h.heappush(minHeap, (intervals[0][1]))

	for i in range(1, len(intervals)):
		curr = intervals[i]
		earliest_end = h.heappop(minHeap)

		if (curr[0] >= earliest_end):
			earliest_end = curr[1]
		else:
			h.heappush(minHeap, curr[1])

		h.heappush(minHeap, earliest_end)


	return len(minHeap)