#!/usr/bin/perl

use strict;
srand(4);

for (1..10){
  &find_a_sufpref_match($_,&generate_random_string(4),&generate_random_string(4),1);
}


sub find_a_sufpref_match {
  my ($id,$a,$b,$msm) = @_;

  my @a = split("",$a);
  my @b = split("",$b);
  my ($start,$length, $m) = (0,0,0);

  for (my $i = @a; $i>=0; $i--){
     my ($x,$mx,$tl,$j) = ($i,0,0,0);
      while( $j <= @a-$i){
        $mx++ if $a[$x] ne $b[$j];
        $tl++;
        if ($mx > $msm){
          if ($j < @a-$i){
            $tl = 0;
          }
          $mx--;
          last;
        }
        $x++;
        $j++;
      }
      ($start,$length,$m) = ($i,$tl-1,$mx) if ($tl -1 > $length)
  }
  print "$id:($m)($start,$length)($a,$b)\n";
}




sub generate_random_string{
  my $length=shift;# the length of the random string to generate

  my @chars= qw(a b);
  my $random_string;
  foreach (1..$length){
    $random_string.=$chars[rand @chars];
  }
  return $random_string;
}