rainerthiel.rb

=begin

The challenge wording leaves some things open so i will assume the following:
- Scheduled arrival can be any time of day or night.
- Arrival can only be late or on time, not early.
- When the arrival time is earlier than the scheduled arrival time
  then that flight has arrived on the following day.
	
So the algorithm only works for arrival times that lie between
scheduled_arrival_time (on time) and 23:59 hours later.

Future challenge:
- Allow early arrivals.
- Allow more than 24h late or early.

=end
time = Regexp.new /([0-1][0-9]|2[0-3]):[0-5][0-9]/

def to_secs(time)
	(time.slice(0..1).to_i * 3600) + (time.slice(3..4).to_i * 60)
end

def to_hhmm(secs)
	daysecs = secs % (3600*24)
	sprintf("%02d:%02d", (daysecs / 3600), (daysecs % 3600)/60)
end

########################
##### SCRIPT STARTS HERE #####
########################
begin
	puts "Usage:"
	puts "#{$0} <scheduled_arrival_time> <actual_arrival_time>..."
	exit
end if ARGV.length < 2

if time.match(ARGV[0])
	sched = to_secs(ARGV[0])
else
	puts "#{ARGV[0]} is not a valid time. Please correct and run again"
	exit
end
arrivals = []
delay_tot = 0
ARGV.delete_at(0) #remove the scheduled arrival time
ARGV.each do |arg|
	if time.match(arg)
		arriv = to_secs(arg)
		delay = arriv - sched
		delay += (24*60*60) if delay < 0
		arrivals << [arriv, delay]
		delay_tot += delay
	else
		puts("**** ERROR: Bad input time #{arg} rejected")
	end
end	

delay_avg = (delay_tot/arrivals.size).to_i
puts "\n\nFor scheduled arrival time #{to_hhmm(sched)}, given the following #{arrivals.size} actual arrival times:"
arrivals.each {|a| puts " => #{to_hhmm(a[0])} (delay #{to_hhmm(a[1]).slice(0..1)} hours and #{to_hhmm(a[1]).slice(3..4)} minutes)"}
puts "The average delay time is #{to_hhmm(delay_avg)}, arriving at #{to_hhmm(sched + delay_avg)}\n\n"