Mapping based on position information

#!/usr/bin/perl
open IN_b, "./first step/candidate_notmatchsanger.txt" or die $!;
open IN_s, "pat_1_result26.txt" or die $!;
open(OUT,">./first step/26.txt")||die "cannot open the dest:$!";

$length = 26;

while(<IN_b>) {
  chomp;
  ($chr,$start,$end,$id,$strand) = split /,/;
  #print $id."\n";
  
  $b_chr = "chr".$chr.$strand;
  push @{ $id{$b_chr} }, $id;
  $start{$id} = $start;
  $end{$id} = $end;
}


while(<IN_s>) {
  chomp;
  ($chr,$id,$start,$strand,$tmp) = split;
  #print $id."\n";


  $s_chr = $chr.$strand;
  $s_start = $start; 
  $s_end = $start + $length;

  $ss = $s_chr;
  foreach $b_id(@{ $id{$ss} }) {
    if ($s_start > $start{$b_id} and $s_end < $end{$b_id}) {
      print OUT "$id\t$b_id\n";
    }
    else {
      #print "$s_start\t$start{$b_id}\t$s_end\t$end{$b_id}\n";
    }
  }
  
}