Programming Challenges

Quote:

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Originally posted by tecknophreak
Aren't there any C/C++/JAVA programers who want to represent?

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Calling me out?
Heheh. I would, but I just accidentally deleted my whole hd. Partitioning error without backing up. (I know, I know... stupid idea) :D

I'm gonna be spending the next few days setting up my new Knoppix/Debian system. If no one has come up with anything, then I'll give it a shot.

While I'm here, I might as wel post another challenge. How about something simple :):
Create a program that inputs a file, replaces all tabs with 3 spaces, and outputs it to another file.

yes i am!

Quote:

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Originally posted by Sepero
While I'm here, I might as wel post another challenge. How about something simple :):
Create a program that inputs a file, replaces all tabs with 3 spaces, and outputs it to another file.

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Another moment to stretch my Python fingers again: (Amendments from Strike to follow ;) )

Code:

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#!/usr/bin/python

import os, re

inputfile="/home/mrben/input.txt"
outputfile="/home/mrben/output.txt"

data=(open(inputfile,'r').read())
output=open(outputfile,'w')

output.write(re.sub('\t','  ',data)

output.close()

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(Strike - could you tell me whether a file gets automatically closed if you read it as part of the open statement, and if not, how to close it?)

You could, of course, implement this in a single Python line from the Python prompt (having imported the relevant libraries)

Code:

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open('/home/mrben/output.txt','w').write(re.sub('\t','  ',(open('/home/mrben/input.txt','r').read())))

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....but you wouldn't want to do that ;)

You can do whole thing in one line if you want.

Code:

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file('/home/mrben/output.txt','w').write(__import__('re').sub('\t','  ',(file('/home/mrben/input.txt','r').read())))

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Notes: use file, not open. Also, if you want to make it neater, you could have something like a NUM_SPACES constant variable and then just sub it with ' ' * NUM_SPACES :)

Quote:

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Originally posted by Strike
You can do whole thing in one line if you want.

Code:

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file('/home/mrben/output.txt','w').write(__import__('re').sub('\t','  ',(file('/home/mrben/input.txt','r').read())))

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Notes: use file, not open. Also, if you want to make it neater, you could have something like a NUM_SPACES constant variable and then just sub it with ' ' * NUM_SPACES :)

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Cheers Strike; knew I could rely on you :D

Python Rocks!

Here is the perl way to the replace tab with three spaces challenge.
Other than opening the file, basically one line to replace and one to write to file.

Code:

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#! /usr/sbin/perl

open (INFILE, "$ARGV[0]") or die "Cannot open file: $ARGV[0] $!";
open (OUTFILE, "> $ARGV[1]") or die "Cannot open file: $ARGV[1] $!";


while(<INFILE>) {
  $_ =~ s/\t/  /g;
  print OUTFILE "$_";
}

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Here is the perl code for the ip parser challenge:

Code:

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#! /usr/sbin/perl

$ip="123.234.21.123";
my $iplong;
my $ip2;
my $delim;
my @len;

if($ip =~ /(\d{2,3})(\.|:)(\d{2,3})(\.|:)(\d{2,3})(\.|:)(\d{2,3})/) {
  $iplong = $1 . $3 . $5 . $7;
  $delim = $2;
 
  if($1/100 >= 1) {$len[0] = 3;} else {$len[0] = 2;}
  if($3/100 >= 1) {$len[1] = 3;} else {$len[1] = 2;}
  if($5/100 >= 1) {$len[2] = 3;} else {$len[2] = 2;}
  if($7/100 >= 1) {$len[3] = 3;} else {$len[3] = 2;}

  print "$iplong\n";
}

if($iplong =~ /\b(\d{$len[0]})(\d{$len[1]})(\d{$len[2]})(\d{$len[3]})\b/) {
  $ip2 = $1 . $delim . $2 . $delim . $3 . $delim . $4;
  print "$ip2\n";
}

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Ok, I might make a fool of myself giving such a simple challenge, but I'm no guru.

Write a program to compute 253 to the 9427th power (or other such ridiculously large numbers).

I've attached the answer, no cheating now!

Okay... I've been working on this for a couple of days now, more off than on. It's a simple pattern matching sort of thing I call MatchScrabble. It works as follows:

A user enters a String of scrambled characters such as "garmrop." The application loads a wordList (a flat file in this case) against which it must find a possible matching word. The basic idea is to unscramble the word and see if exists in the word list. To continue the example -- say we have a wordList constructed as follows:
---------
program
entry
situation
telling
stop
progrom
tron
more
vortex
teeth
seriously
poor
people
pudding
stopping
starting
eating
drinking
--------

The user enters the string "garmrop." The application should attempt to find a match for this in the word list. In this case the match would be on the first entry: "program" so your app, given that input against that wordList, should return a match on the word 'program.' I'd like to make it efficient enough so that it scales to very long wordLists, eventually using the entries in the Oxford English Dictionary as the wordList.

Simple, right?

Quote:

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Originally posted by Sepero
Calling me out?
Heheh. I would, but I just accidentally deleted my whole hd. Partitioning error without backing up. (I know, I know... stupid idea) :D

I'm gonna be spending the next few days setting up my new Knoppix/Debian system. If no one has come up with anything, then I'll give it a shot.

While I'm here, I might as wel post another challenge. How about something simple :):
Create a program that inputs a file, replaces all tabs with 3 spaces, and outputs it to another file.

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Though this doesn't really fit into the programming challenge I'd use sed to accomplish this:

cat $file |sed 's/[TAB]/[3SPACES/' > $newfile

Sometimes the best programming is using the tools already present :)

#!/usr/bin/perl -w

while(<>) {
s/\t/ /;
print;
}

Quote:

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Originally posted by hotleadpdx
cat $file |sed 's/[TAB]/[3SPACES/' > $newfile

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You don't even need to use cat for that (this is one of the Useless Uses of Cat, congratulations! :p)

You can do this instead:

sed -e 's/[TAB]/[3 SPACES]/' <$file >$newfile

Or, better yet, do it in-place (only works with recent versions of sed):

sed -i -e 's/[TAB]/[3 SPACES]/' $file

"Useless Uses of Cat" :) How amusing :) Where's the list kept? Using cat is a bad habit of mine from working with compressed files all day (zcat $file | blah blah...). But! If there's a sed command line option that allows it to read a compressed file I'll change my ways :)

Quote:

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Originally posted by Ratboy68
Okay... I've been working on this for a couple of days now, more off than on. It's a simple pattern matching sort of thing I call MatchScrabble. It works as follows:

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I cheated and used /usr/shared/dict/words as the dictionary, it can be modified to look where ever it wants, just add a -f /location to the args and look for it.

[edit]I don't want to hear anyone yelling at me about using "using namespace std;", cause it's just a little prog[/edit]

Quote:

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Originally posted by tecknophreak
[edit]I don't want to hear anyone yelling at me about using "using namespace std;", cause it's just a little prog[/edit]

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Aww, come on! I want to yell at you about it! (... or, uh, something...)

:p

Quote:

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Originally posted by hotleadpdx
"Useless Uses of Cat" :) How amusing :) Where's the list kept?

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http://rhols66.adsl.netsonic.fi/era/unix/award.html ;)