find at what time the maximum number of people will be in the party .

Found This Question on One of the Forum :D & posting here as thought it  seems to be something interesting :) There is a list containing the checkin and checkout time of every person in a party . The checkin time is in ascending order while the checkout is random .

Eg:

                       Check_in                Check_out

Person 1             8.00                          9.00

Person 2             8.15                          8.30

Person 3             8.30                          9.20

and so on ...Now , give an optimized solution to find at what time the maximum number of people will be in the party . 

Algorithm

It has the same Algorithm  That  We have been used to solve Bus-Station Problem :)

Time Compelxity O(nlogn)

Space Complexity O(1)