my (UInt $tx0, Int $ty0, UInt $tx1, Int $ty1);
sub shoot(UInt:D $xv is copy, Int:D $yv is copy --> Real:D) {
my ($x, $y) X= 0;
my Real $besty = -∞;
loop {
return $besty if $tx0 ≤ $x ≤ $tx1 and $ty0 ≤ $y ≤ $ty1;
return -∞ if $x > $tx1;
return -∞ if $y < $ty0;
$x += $xv;
$y += $yv--;
if $xv > 0 {
--$xv;
} elsif $xv < 0 {
++$xv;
}
$besty = $y if $y > $besty;
}
}
($tx0, $tx1, $ty0, $ty1) = $*IN.slurp.comb(/'-'?\d+/)».Int;
put 'part 1: ', (1..$tx1 X 1..(-$ty0-1)).map({ shoot(.[0], .[1]) }).max;
put 'part 2: ', (1..$tx1 X $ty0..(-$ty0-1)).grep({ shoot(.[0], .[1]) > -∞ }).elems;
