#!c:/perl/bin/perl.exe 
# make sure you "hardwire" in your word list (see 8 lines down).
use integer;  # so the calculation of $mid will be integers
$words="";
($anagram,$words)=@ARGV;
if ($anagram eq ""){
  print "Usage: Perl anagram.pl anagram dictionary";
  exit;
}

if ($words eq "") {
   #$words="c:/windows/desktop/perlhtml/SmallWordList.txt";
   $words="c:/BigWordList.txt";
}

open WORDS, $words or die "Cannot open $words for read :$!";

chomp (@list=<WORDS>); 
$st=&getpermutations($anagram);
for $temp (@$st){
  if (binarysearch($temp)) {
     print "anagram: $temp \n";
  }
}

# this subroutine converts strings to arrays so they can be fed to 
# subroutine permute.  They take the returned arrayref and reformat it so  
# that individual elements are words not individual letters.
sub getpermutations {
  my ($str)=@_;
  @array=split //, $str;
  $length=$#array+1;
  $answer=&permute([@array], []);


  $fact=&factorial($length);


  for ($i=0;$i<$fact;$i++) {
    $string[$i]="";
    for ($j=0;$j<$length;$j++) {
      $string[$i].=@$answer[$i*$length+$j];
    }
  }
return (\@string);
} 

  
sub factorial {
  my ($temp)=@_;
  if ($temp>1) {
    return $temp*factorial($temp-1);
  }
  if ($temp==1) {
    return 1;
  }
}
# sub permute is a slightly modified version of a subroutine I found in
# the CORE perl FAQs.  I return an arrayref rather than print out # permutations
sub permute {
  my @items = @{ $_[0] };
  my @perms = @{ $_[1] };
    unless (@items) {
       push (@output,@perms);
    } else {
       my(@newitems,@newperms,$i);
       foreach $i (0 .. $#items) {
         @newitems = @items;
         @newperms = @perms;
         unshift(@newperms, splice(@newitems, $i, 1));
         permute([@newitems], [@newperms]);
       }
     }
return (\@output);
}


sub binarysearch {
  my ($myword)=@_;
 
  $low=0;
  $high=$#list;
  $mid=($high+$low)/2;
  for(;;){
     if (($high-$low)<3) {
       last;
    }
    if ($myword lt $list[$mid]) {
      $high=$mid;
      $mid=($high+$low)/2;
    }
    if ($myword gt $list[$mid]) {
      $low=$mid;
      $mid=($high+$low)/2;
    }
    if ($myword eq $list[$mid]) {
      return 1;
    }
  }
  
  foreach $word (@list[$low..$high]) {
    if ($myword eq $word) {
      return 1;
    }
  }
return 0;
}