sub Apply_on_index(&@)  
{  
my $func = shift;  
my $array = shift;  
my $group = shift;  
return undef unless (defined $func and defined $array);  
my $rest;  
my $i;  
my $j;  
my @array;  
my $size = $#{$array}+1;  
my $card = factorial($size);  
my $res;  
for($j=0;$j<$card;$j++){  
@array = @{$array};  
$res = [];  
$rest = $j;  
$i = 0;  
for($i = 0; $i <= $#{$array}; $i++){  
${$res}[$i] = splice @array, $rest % ($#array + 1), 1;  
$rest = int($rest / ($#array + 2));  
if ($i > 0 and ${$res}[$i] < ${$res}[$i-1] and  
${$group}[${$res}[$i]] == ${$group}[${$res}[$i-1]]){  
$res = undef;  
last;  
}  
}  
&$func($j) if defined $res;  
}  
return 0;  
}