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#!/usr/bin/perl
#-------------------------------------------------------------------------------
sub bitmask {
local ($low,$high,$top)=(@_);
return if($low>$high);
# get highest bit needed for calculation
if($top eq ""){
for($top=1;$top<$high;$top*=2){}
}
for(local $i=$top;$i>=1;$i/=2) {
for(local $j=0;$j<=$top;$j+=$i) {
if($j>=$low&&$j+$i-1<=$high) {
return(&bitmask($low,$j-1,$top),
"$j-". ( $j + ( $i - 1 ) ) ."/$i",
&bitmask($j+$i,$high,$top));
}
}
}
}
for(@ARGV) {
/^[0-9]+-[0-9]+$/ && do {
@a=split("-",$_);
if($a[0]>$a[1]) {
warn "first number must be smaller in a sequence\n";
next;
}
print "[$a[0]-$a[1]]\n";
print " ".join("\n ",&bitmask(@a))."\n";
next;
};
warn "\"$_\" not expected\n";
}
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