#!/usr/bin/perl
#

$max=44;
$moves=0;
%boardx;
$boardx{'A'}=0;$boardy{'A'}=0;
$boardx{'B'}=$max;$boardy{'B'}=0;
$boardx{'C'}=$max;$boardy{'C'}=$max;
$boardx{'Z'}=$max;$boardy{'Z'}=$max;
sub collide{
        if ($boardx{'Z'} <0){ return 1;}
        if ($boardy{'Z'} <0) {return 1;}
        if ($boardx{'Z'} >$max){ return 1;}
        if ($boardy{'Z'} >$max){ return 1;}

        if  (($boardx{'Z'}==$boardx{'A'})  && ($boardy{'Z'}==$boardy{'A'}))  {return 1;}
        if  (($boardx{'Z'}==$boardx{'B'})  && ($boardy{'Z'}==$boardy{'B'})) { return 1;}
        if  (($boardx{'Z'}==$boardx{'C'})  && ($boardy{'Z'}==$boardy{'C'})) { return 1;}
        return(0);

}

sub printBoard{
        print "\n";
        for($i=0;$i<=$max;$i++){

                for($j=0;$j<=$max;$j++){
                        $zed=1;
                        foreach ('A','B','C'){
                                if (($boardx{$_}==$j) && ($boardy{$_}==$i)){
                                        print $_;
                                        $zed=0;
                                }

                        }
                        if ($zed){ print '.';}
                }
                print "\n";
        }
}
sub move{
        $block=shift(@_);
        $dir=shift(@_);# 0-3 nesw or urdl
        $boardx{'Z'}=$boardx{$block};
        $boardy{'Z'}=$boardy{$block};
        if ($dir==0){$boardy{'Z'}--;}
        if ($dir==1){$boardx{'Z'}++;}
        if ($dir==2){$boardy{'Z'}++;}
        if ($dir==3){$boardx{'Z'}--;}
        if (&collide){$moves++; return;}

        $boardx{$block}=$boardx{'Z'};
        $boardy{$block}=$boardy{'Z'};

        &move($block,$dir);
}
sub dinkUp{
        #assumes An A-left B left, C right Low
        &move('A',1);
        &move('B',0);
        &move('A',3);
        &move('B',2);
        &move('B',1);
        &move('A',0);
        &move('B',3);
        &move('A',2);
}
sub dinkSide{
        #assumes An A-left , C right , b RIGHT LOW
        &move('C',3);
        &move('A',0);
        &move('A',1);
        &move('A',2);
        &move('A',3);
        if ($boardx{'A'}==$max/2){return;}
        &move('C',0);
        &move('C',1);
        &move('C',2);
}


&printBoard;
&move('B',2);
&move('B',3);
&move('A',2);
&printBoard;
while ($boardy{'A'} > $max/2+1){
        &dinkUp;
}
if ($boardy{'A'}==$max/2){
        &move('C',0);
        &move('B',1);
        &move('C',2);
}

if ($boardy{'A'}>$max/2){
        &move('C',0);
        &move('A',1);
        &move('C',2);
        &move('B',0);
        &move('A',3);
        &move('B',2);
}
## ISO-STABILIZATION

&printBoard;
print "Isoform:\n";
$boardx{'A'}=0;$boardy{'A'}=$max/2;
$boardx{'B'}=$max;$boardy{'B'}=$max/2+1;
$boardx{'C'}=$max;$boardy{'C'}=$max/2;
&printBoard;
while ($boardx{'A'} < $max/2-1){
        &dinkSide;
}
if ($boardx{'A'}<$max/2){
        &move('C',3);
}
&printBoard;
print "moves: $moves\n";