use strict;
use warnings;

my (@r1, %r1, @r2, $i, $j, $inp, $start, $end, $choice);

@r1 = (
    { 'name' => 'b', 'start' => 70, 'end' => 110 },
    { 'name' => 'c', 'start' => 40, 'end' => 80 },
    { 'name' => 'd', 'start' => 80, 'end' => 140 },
    { 'name' => 'e', 'start' => 30, 'end' => 100 },
);

for (@r1) {
    $r1{$_->{'name'}}++;
    $_->{'stages'} = 1;
}

### Generate combinations of overlapping ranges
do {
    @r2 = ();
    for $i (0..$#r1) {
        for $j (0..$#r1) {
            ### Ranges are same, skip
            next if $i == $j;
    
            ### One range is completely inside other, skip
            next if $r1[$i]{'start'} <= $r1[$j]{'start'} &&
                    $r1[$i]{'end'} >= $r1[$j]{'end'} ||
                    $r1[$j]{'start'} <= $r1[$i]{'start'} &&
                    $r1[$j]{'end'} >= $r1[$i]{'end'};
    
            ### i is not earlier range, skip
            next if $r1[$j]{'start'} < $r1[$i]{'start'};
    
            ### Ranges do not overlap at all, skip
            next if $r1[$i]{'end'} < $r1[$j]{'start'};
            
            ### Combined range already exists, skip
            next if $r1{"$r1[$i]{'name'}-$r1[$j]{'name'}"}++;
            
            ### Combine and add
            push @r2, {
                name => "$r1[$i]{'name'}-$r1[$j]{'name'}",
                start => $r1[$i]{'start'},
                end => $r1[$j]{'end'},
                stages => $r1[$i]{'stages'} + $r1[$j]{'stages'}
            };
        }
    }
    push @r1, @r2;
}
while ($#r2 != -1);

while (1) {
    print "\n";
    exit if !getInputYes('Do you want to match a range?');
    $start = int getInput('Enter a start value');
    $end = int getInput('Enter an end value');
    
    @r2 = ();
    for (@r1) {
        $_->{'diff'} = $start - $_->{'start'} + $_->{'end'} - $end;
        push @r2, $_
            if $start >= $_->{'start'} &&
               $end <= $_->{'end'};
    }

    if ($#r2 == -1) {
        print "No matches found.\n";
        next;
    }
    
    for (sort {
        $a->{'diff'} <=> $b->{'diff'} ||
        $a->{'stages'} <=> $b->{'stages'} 
    } @r2) {
        print "$_->{'name'} [$_->{'start'}-$_->{'end'}] is best match, with $_->{'diff'} difference and $_->{'stages'} stages.\n";
        last;
    }
}

sub getInput {
    my $inp;
    while (1) {
        print "$_[0] : ";
        chomp($inp = <STDIN>);
        return $inp if $inp;
    }
}
sub getInputYes {
    my $inp;
    while (1) {
        $inp = uc substr(getInput("$_[0] (Y/N)"), 0, 1);
        return 1 if $inp eq 'Y';
        return 0 if $inp eq 'N';
    };
}