coderloop: src/reverse_seq.pl annotate

initial committ

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rlm@0	1 #!/usr/bin/perl
rlm@0	2
rlm@0	3 $a = "/home/r/coderloop-test/reversesequence-a.in";
rlm@0	4 $b = "/home/r/coderloop-test/reversesequence-b.in";
rlm@0	5 $c = "/home/r/coderloop-test/reversesequence-c.in";
rlm@0	6
rlm@0	7 %test_map = ("a" => "b", "b" => "c");
rlm@0	8
rlm@0	9 sub create_map{
rlm@0	10 ## creates a "linked map" from a string representing
rlm@0	11 ## the input file.
rlm@0	12 (my $file) = @_;
rlm@0	13 my %map;
rlm@0	14 open FILE, "<".$file or die $!;
rlm@0	15 for (<FILE>){ chomp; /^(\w+)\W+(\w+)$/; $map{$1} = $2;}
rlm@0	16 close FILE;
rlm@0	17 return %map;}
rlm@0	18
rlm@0	19 sub find_beginning{
rlm@0	20 ## takes a map representing a linked list and
rlm@0	21 ## returns the beginning of that list.
rlm@0	22 (my %map) = @_;
rlm@0	23 my %val_set = map {$_ => 1} (values %map);
rlm@0	24 my $start;
rlm@0	25 foreach (keys %map){
rlm@0	26 if (!($val_set{$_})){$start = $_;last}}
rlm@0	27 return $start;}
rlm@0	28
rlm@0	29 sub trace_map{
rlm@0	30 ## crawls through a map representing a linked-list
rlm@0	31 ## and converts it into an actual array structure.
rlm@0	32 (my %map) = @_;
rlm@0	33 my $position = &find_beginning(%map);
rlm@0	34 my @array = ($position);
rlm@0	35 while(my $new_position = $map{$position}){
rlm@0	36 push (@array, $new_position);
rlm@0	37 $position = $new_position;}
rlm@0	38 return @array;}
rlm@0	39
rlm@0	40
rlm@0	41
rlm@0	42 if (defined @ARGV){
rlm@0	43 map {print;print"\n";} reverse(trace_map(create_map($ARGV[0])));}

Mercurial > coderloop