Class PQ4

java.lang.Object

PQ4

public class PQ4
extends java.lang.Object

Field Summary

Fields

Modifier and Type	Field and Description
(package private) static Node	root

Constructor Summary

Constructors

Constructor and Description
PQ4()

Method Summary

Modifier and Type	Method and Description
(package private) static void	buildTree(char[] letters) Add letters to ternary tree using a level-order traversal (breadth first search).
static void	main(java.lang.String[] args)
(package private) static void	printTree(Node current, java.lang.String answer) Traverse the tree using recursion and print the letters contained in every path from the root to a leaf node.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

root

static Node root

Constructor Detail

PQ4

public PQ4()

Method Detail

main

public static void main(java.lang.String[] args)

buildTree

static void buildTree(char[] letters)

Add letters to ternary tree using a level-order traversal (breadth first search).

Take a moment to look over the setup code and implement the while loop.

1. Remove a node, curr, from the Queue and assign it into a temporary variable
2. Assign the next three letters to curr's left, center, and right children.
3. Add the children into the queue in the same order as above.

You can assume that char[] letters will always contain i * 3 + 1 letters.

Parameters:

letters - an array of letters

printTree

static void printTree(Node current,
                      java.lang.String answer)

Traverse the tree using recursion and print the letters contained in every path from the root to a leaf node.

Follow this algorithm:

1. If the node specified is null, return immediately. This is a base case.
2. Add the letter contained in the current node to the answer string.
3. Check whether the node is a leaf node (if all children references are null).
4. If all children are null, print the answer string.
5. If not, call printTree recursively for the left, center, and right children, in that order.

Parameters:

current - a reference to the tree node

answer - a string