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: Accepted)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.io.StreamTokenizer;
import java.util.InputMismatchException;


public class Main {

	public static Node[] nodes;

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in); 
		Printer pr = new Printer(System.out);

		int n = sc.nextInt();
		nodes = new Node[n];
		
    	for (int i = 0; i < n; i++) {
    		int id = sc.nextInt();
    		nodes[id] = new Node(id, sc.nextInt(), sc.nextInt());
    	}

    	for (int i = 0; i < n; i++) {
    		setParent(i);
    	}
    	int root = seekRoot();
    	setDepth(root, 0);
    	for (int i = 0; i < n; i++) {
        	setHeight(i);
    	}


    	for (int i = 0; i < n; i++) {
    		pr.println(nodes[i].toString());
    	}
    	
    	pr.close();
        sc.close();
	}
	
	private static void setParent(int id) {
		nodes[id].degree = 0;
		if (nodes[id].l_child != -1) {
			nodes[nodes[id].l_child].parent = id;
			nodes[id].degree++;
		}
		if (nodes[id].r_child != -1) {
			nodes[nodes[id].r_child].parent = id;
			nodes[id].degree++;
		}
	}
	
	private static int seekRoot() {
    	for (int i = 0; i < nodes.length; i++) {
    		if (nodes[i].parent == -1){
    			return i;
    		}
    	}
    	
    	return -1;
	}
	
	private static void setDepth(int id, int depth) {
		if (nodes[id].parent == -1) {
			nodes[id].type = NodeType.ROOT;
		} else {
			if (nodes[id].degree == 0) {
				nodes[id].type = NodeType.LEAF;
				nodes[id].height = 0;
			} else {
				nodes[id].type = NodeType.INTERNAL_NODE;
				nodes[id].height = -1;
			}
		}
		nodes[id].depth = depth;

		if (nodes[id].degree == 2) {
			nodes[nodes[id].l_child].sibling = nodes[id].r_child;
			nodes[nodes[id].r_child].sibling = nodes[id].l_child;
		}
		
		if (nodes[id].l_child != -1) {
			setDepth(nodes[id].l_child, depth + 1);
		}
		if (nodes[id].r_child != -1) {
			setDepth(nodes[id].r_child, depth + 1);
		}

		return;
	}
		
	private static void setHeight(int id) {
		if (nodes[id].height != 0) {
			return;
		} else {
			for (int j = nodes[id].parent, h = 0; j != -1; j = nodes[j].parent, h++) {
				if (nodes[j].height < h + 1) {
					nodes[j].height = h + 1;
				}
			}
		}
	}

	private static enum NodeType {
		ROOT, INTERNAL_NODE, LEAF;
	}
	
	private static class Node {
		public int id;
		public int parent;
		public int l_child;
		public int r_child;
		public int sibling;
		public int depth;
		public int height;
		public int degree;
		public NodeType type;
	
		public Node(int id, int l_child, int r_child) {
			this.id = id;
			this.l_child = l_child;
			this.r_child = r_child;
			this.sibling = -1;
			this.parent = -1;
		}
		
		@Override
		public String toString() {
			StringBuffer str = new StringBuffer();

			str.append("node ");
			str.append(id);
			str.append(": parent = ");
			str.append(parent);
			str.append(", sibling = ");
			str.append(sibling);
			str.append(", degree = ");
			str.append(degree);
			str.append(", depth = ");
			str.append(depth);
			str.append(", height = ");
			str.append(height);
			str.append(", ");
			String type;
			switch (nodes[id].type) {
			case INTERNAL_NODE:
				type = "internal node";
				break;
			case LEAF:
				type = "leaf";
				break;
			case ROOT:
				type = "root";
				break;
			default:
				type = null;
			}
			str.append(type);
			
			return str.toString();
		}
	}


	private static class Scanner {
		InputStreamReader isr;
		BufferedReader br;
		StreamTokenizer st;
		
		Scanner (InputStream in) {
			isr = new InputStreamReader(in);
			br = new BufferedReader(isr);
			st = new StreamTokenizer(br);
		}
		
		String next() throws RuntimeException  {
			try {
				if (st.nextToken() != StreamTokenizer.TT_WORD) {
				}
			} catch (IOException e) {
				throw new IllegalStateException();
			}
			
			return st.sval;
		}
		
		int nextInt() throws RuntimeException {
			try {
				if (st.nextToken() != StreamTokenizer.TT_NUMBER) {
					throw new InputMismatchException();
				}
			} catch (IOException e) {
				throw new IllegalStateException();
			}
			
			return (int)st.nval;
		}

		void close() {
		}
	}
	
	private static class Printer {
		PrintStream out;
		StringBuffer strbuf;
		int bufSize;
		final String CR;

		Printer(PrintStream out) {
			this.out = out;
			strbuf = new StringBuffer();
			bufSize = 64 * 1024;
			CR = System.getProperty("line.separator");
		}

		void println(String str) {
			strbuf.append(str);
			strbuf.append(CR);
			checkStringBuffer();
		}

		void print(String str) {
			strbuf.append(str);
			checkStringBuffer();
		}

		void println(int n) {
			strbuf.append(n);
			strbuf.append(CR);
			checkStringBuffer();
		}

		void print(int n) {
			strbuf.append(n);
			checkStringBuffer();
		}

		void print(char c) {
			strbuf.append(c);
			checkStringBuffer();
		}

		void printArray(int[] array) {
			for (int i = 0; i < array.length; i++) {
				checkStringBuffer();
				strbuf.append(array[i]);
				strbuf.append(" ");
			}
			strbuf.delete(strbuf.length() - 1, strbuf.length());
			strbuf.append(CR);
		}

		void close() {
			flashStringBuffer();
		}
		
		private void flashStringBuffer() {
			if (strbuf.length() > 0) {
				out.print(strbuf);
				strbuf.setLength(0);
			}
		}
		
		private void checkStringBuffer() {
			if (strbuf.length() > bufSize) {
				out.print(strbuf);
				strbuf.setLength(0);
			}
		}
	}
}