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# Test: perl6 ch-2.p6 4
class BTree::Node {
has Int $.value is rw;
has BTree::Node $.left is rw;
has BTree::Node $.right is rw;
}
sub MAIN() {
my $root =
BTree::Node.new(
value => 5,
left => BTree::Node.new(
value => 4,
left => BTree::Node.new(
value => 11,
left => BTree::Node.new(
value => 7
),
right => BTree::Node.new(
value => 2,
)
)
),
right => BTree::Node.new(
value => 8,
left => BTree::Node.new(
value => 13
),
right => BTree::Node.new(
value => 9,
right => BTree::Node.new(
value => 1,
)
)
)
);
my $k = 22;
path-sum($root, $k, 0, '');
}
sub path-sum(BTree::Node $node, Int $k, Int $total is copy, Str $path_string is copy) {
$total += $node.value;
$path_string ~= $node.value;
# Branch left
path-sum( $node.left,
$k,
$total,
$path_string ~ ' → ' )
if ($node.left);
# Branch right
path-sum($node.right,
$k,
$total,
$path_string ~ ' → ' )
if ($node.right);
# Calculate total if we can't branch
if ( !$node.left &&
!$node.right &&
$total == $k ) {
say $path_string;
}
}
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