RosettaCodeData/Task/Tree-traversal/Ceylon/tree-traversal.ceylon

98 lines
1.6 KiB
Ceylon

import ceylon.collection {
ArrayList
}
shared void run() {
class Node(label, left = null, right = null) {
shared Integer label;
shared Node? left;
shared Node? right;
string => label.string;
}
void preorder(Node node) {
process.write(node.string + " ");
if(exists left = node.left) {
preorder(left);
}
if(exists right = node.right) {
preorder(right);
}
}
void inorder(Node node) {
if(exists left = node.left) {
inorder(left);
}
process.write(node.string + " ");
if(exists right = node.right) {
inorder(right);
}
}
void postorder(Node node) {
if(exists left = node.left) {
postorder(left);
}
if(exists right = node.right) {
postorder(right);
}
process.write(node.string + " ");
}
void levelOrder(Node node) {
value nodes = ArrayList<Node> {node};
while(exists current = nodes.accept()) {
process.write(current.string + " ");
if(exists left = current.left) {
nodes.offer(left);
}
if(exists right = current.right) {
nodes.offer(right);
}
}
}
value tree = Node {
label = 1;
left = Node {
label = 2;
left = Node {
label = 4;
left = Node {
label = 7;
};
};
right = Node {
label = 5;
};
};
right = Node {
label = 3;
left = Node {
label = 6;
left = Node {
label = 8;
};
right = Node {
label = 9;
};
};
};
};
process.write("preorder: ");
preorder(tree);
print("");
process.write("inorder: ");
inorder(tree);
print("");
process.write("postorder: ");
postorder(tree);
print("");
process.write("levelorder: ");
levelOrder(tree);
print("");
}