Problem:
Binary Tree

A rooted binary tree is a tree with a root node in which every node has at most two children.

Your task is to write a program which reads a rooted binary tree T and prints the following information for each node u of T:

node ID of u

parent of u

sibling of u

the number of children of u

depth of u

height of u

node type (root, internal node or leaf)

If two nodes have the same parent, they are siblings. Here, if u and v have the same parent, we say u is a sibling of v (vice versa).

The height of a node in a tree is the number of edges on the longest simple downward path from the node to a leaf.

Here, the given binary tree consists of n nodes and evey node has a unique ID from 0 to n-1.

Input

The first line of the input includes an integer n, the number of nodes of the tree.

In the next n lines, the information of each node is given in the following format:

id left right

id is the node ID, left is ID of the left child and right is ID of the right child. If the node does not have the left (right) child, the left(right) is indicated by -1.

Output

Print the information of each node in the following format:

node id: parent = p, sibling = s, degree = deg, depth = dep, height = h, type

p is ID of its parent. If the node does not have a parent, print -1.

s is ID of its sibling. If the node does not have a sibling, print -1.

deg, dep and h are the number of children, depth and height of the node respectively.

type is a type of nodes represented by a string (root, internal node or leaf. If the root can be considered as a leaf or an internal node, print root.

Please follow the format presented in a sample output below.

Constraints

1 ≤ n ≤ 25

Sample Input 1

9
0 1 4
1 2 3
2 -1 -1
3 -1 -1
4 5 8
5 6 7
6 -1 -1
7 -1 -1
8 -1 -1

Sample Output 1

node 0: parent = -1, sibling = -1, degree = 2, depth = 0, height = 3, root
node 1: parent = 0, sibling = 4, degree = 2, depth = 1, height = 1, internal node
node 2: parent = 1, sibling = 3, degree = 0, depth = 2, height = 0, leaf
node 3: parent = 1, sibling = 2, degree = 0, depth = 2, height = 0, leaf
node 4: parent = 0, sibling = 1, degree = 2, depth = 1, height = 2, internal node
node 5: parent = 4, sibling = 8, degree = 2, depth = 2, height = 1, internal node
node 6: parent = 5, sibling = 7, degree = 0, depth = 3, height = 0, leaf
node 7: parent = 5, sibling = 6, degree = 0, depth = 3, height = 0, leaf
node 8: parent = 4, sibling = 5, degree = 0, depth = 2, height = 0, leaf

Reference

Introduction to Algorithms, Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, and Clifford Stein. The MIT Press.

Solution in JAVA (judge verdict: Wrong Answer)


import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StreamTokenizer;
import java.util.Arrays;
import java.util.HashMap;

public class Main {

	class Node {
		public Node(int left, int right) {
			this.left = left;
			this.right = right;
		}

		int parent = -1;
		int left;
		int right;
		int sibling = -1;
		int depth = 0;
		int degree;
		int height;
		String type;

		public String toString() {
			return ": parent = " + parent + ", sibling = " + +sibling + ", degree = " + degree + ", depth = " + depth
					+ ", height = " + height + ", " + type;
		}
	}

	HashMap<Integer, Node> nodes = new HashMap<>();

	private void solv() {
		Scanner input = new Scanner(System.in);
		int n = input.nextInt();
		int[] keys = new int[n];

		for (int i = 0; i < n; i++) {
			int id = input.nextInt();
			int left = input.nextInt();
			int right = input.nextInt();
			Node node = new Node(left, right);
			nodes.put(id, node);
			keys[i] = id;
		}

		// height
		for (int target : keys) {
			Node node = nodes.get(target);
			node.height = calcHeight(target);
		}

		// degree
		for (int target : keys) {
			Node node = nodes.get(target);
			if (node.left == -1 && node.right == -1) {
				node.degree = -0;
			} else {
				node.degree = 2;
			}
		}

		// parent
		for (int target : keys) {
			Node node = nodes.get(target);
			for (int i : keys) {
				if (nodes.get(i).left == target || nodes.get(i).right == target) {
					node.parent = i;
					break;
				}
			}
		}

		// depth
		for (int target : keys) {
			int depth = 0;
			Node node = nodes.get(target);
			while (node.parent != -1) {
				node = nodes.get(node.parent);
				depth++;
			}
			nodes.get(target).depth = depth;
		}

		// sibling
		for (int target : keys) {
			Node node = nodes.get(target);
			int left = node.left;
			int right = node.right;
			if (left != -1 && right != -1) {
				nodes.get(left).sibling = right;
				nodes.get(right).sibling = left;
			}
		}
		
		// type
		for (int target : keys) {
			Node node = nodes.get(target);
			if (node.parent == -1) {
				node.type = "root";
			} else if (node.degree == 0) {
				node.type = "leaf";
			} else {
				node.type = "internal node";
			}
		}

		Arrays.sort(keys);
		for (int i : keys) {
			System.out.println("node " + i + nodes.get(i));
		}

	}

	public int calcHeight(int key) {
		int h1 = 0;
		int h2 = 0;
		if (nodes.get(key).right != -1) {
			h1 = calcHeight(nodes.get(key).right) + 1;
		}
		if (nodes.get(key).left != -1) {
			h2 = calcHeight(nodes.get(key).left) + 1;
		}
		return Math.max(h1, h2);
	}

	public static void main(String[] args) {
		Main main = new Main();
		main.solv();
	}

	private void print(Object[] xs) {
		StringBuilder sb = new StringBuilder();
		for (Object x : xs)
			sb.append(x.toString()).append(' ');
		System.out.println(sb.toString().trim());
	}

	private void print(int[] xs) {
		StringBuilder sb = new StringBuilder();
		for (int i = 1; i < xs.length; i++) {
			sb.append(xs[i]).append(' ');
		}
		System.out.println(sb.toString().trim());
	}

	private static class Scanner {
		BufferedReader r;
		StreamTokenizer st;

		public Scanner(InputStream in) {
			r = new BufferedReader(new InputStreamReader(in));
			st = new StreamTokenizer(r);
		}

		public String next() {
			nextToken();
			return st.sval;
		}

		public Integer nextInt() {
			nextToken();
			return (int) st.nval;
		}

		private int nextToken() {
			int token = st.TT_EOF;
			try {
				token = st.nextToken();
			} catch (IOException e) {
			}
			return token;
		}
	}

}