[Haskell-cafe] Re: On the verge of ... giving up!

Prabhakar Ragde plragde at uwaterloo.ca
Sun Oct 14 15:33:03 EDT 2007


apfelmus wrote:

>> I mean, contemplate this trivial exercise for a moment: write a program 
>> > that reads from stdin a series of numbers (one number per line), and 
>> > writes out the sum of the last n numbers.  This is a trivial problem, 
>> > and I have no doubt that someone who knows Haskell better than I will 
>> > reply to this email with a single line of code that does it.
> 
> Sorry, I can't resist  :) 
> 
> main n = print . sum . map read . take n . reverse . lines =<< getContents

Could someone describe succinctly how to compute the space complexity of 
this program, if there are m lines of input and m >> n? Many thanks. --PR


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