A list of flights. Each line specifies the source city, the destination
city, the departure time, the arrival time and the one-way and round-trip
fares (in Indian Rupees).
Part 1
Write a function that accepts as input
a source city S,
a destination city D, and
a time t of travel,
and that computes
a travel plan for the S-to-D jouney with minimum time, and
a travel plan for the S-to-D jouney with minimum cost.
A passenger must be given time for check-in and transit, and all
these must happen after the specified time t. Here the time of
travel is measured by the arrival time at D minus t.
Part 2
Write another function that accepts as input
a source city S,
a destination city D,
a time t1 of onward travel, and
a time t2 of return travel,
and that computes
a travel plan for the S-to-D-backto-S jouney with minimum time, and
a travel plan for the S-to-D-backto-S jouney with minimum cost.
Here the total time of travel is (the arrival time at D minus t1)
+ (the arrival time at S minus t2).