Binary tree in java
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The document describes a Java program for a binary tree that extends the functionalities of a superclass called SimpleTree. It includes various methods for counting leaves, checking if nodes have two children or none, and removing leaf nodes. Key methods implemented include countLeaves, twoChildrenOrNone, and trim, which handle tree operations based on the structure of the binary tree.
Binary tree in java
- 2. Binary Tree in Java Thisis a program of a binary tree which is extended from its super class SimpleTree. It uses all the functionalities from its super class. A binary tree consists of two leaves mainly left child nodes and right child nodes. There are different methods defined performing different functionalities. Initially it is checked whether the root node is created for a binary tree or not. Another method is counting for the leaves of the binary tree, by counting the left and right child nodes. Some method is checking for the nodes having both the child nodes available or not. Also methods are modifying and removing the required nodes. public class BinaryTree extends SimpleTree { // counting leaves public int countLeaves() { if (root == null) { return 0; } else { return countLeaves(root); } } /* * determine how many leaves are in the subtree whose root is node * Precondition: node is not null */ private int countLeaves(Node n) { BinaryNode node = (BinaryNode) n; if ((node.getLeft()==null) && (node.getRight()==null)) { return 1; } else if ((node.getLeft()==null) && (node.getRight()!=null)) { return countLeaves(node.getRight()); } else if ((node.getLeft()!=null) && (node.getRight()==null)) { return countLeaves(node.getLeft()); } else { // this is done when // ((node.getLeft()!=null) && (node.getRight()!=null)) return countLeaves(node.getLeft()) + countLeaves(node.getRight()); } } // count nodes
- 3. /** * return true when every node in the tree has either two children or none * (but no node has only one child) */ public boolean twoChildrenOrNone() { if (root == null) { return true; } else { return twoChildrenOrNone(root); } } /* * determine whether all the node has two children or none * Precondition: node is not null */ private boolean twoChildrenOrNone(Node n) { BinaryNode node = (BinaryNode) n; if ((node.getLeft()==null) && (node.getRight()==null)) { return true; } else if ((node.getLeft()==null) && (node.getRight()!=null)) { return false; } else if ((node.getLeft()!=null) && (node.getRight()==null)) { return false; } else { // this is done when // ((node.getLeft()!=null) && (node.getRight()!=null)) return twoChildrenOrNone(node.getLeft()) && twoChildrenOrNone(node.getRight()); } } // remove leaves /** * modify the tree by removing every leaf node */ public void trim() { if (root != null) { root = trim(root); } } /* * remove all the leaves. * Precondition: node is not null */ private BinaryNode trim(Node n) { BinaryNode node = (BinaryNode) n; if ((node.getLeft()==null) && (node.getRight()==null)) {
- 4. // this is a leaf, remove it from the tree. return null; } else if ((node.getLeft()==null) && (node.getRight()!=null)) { node.setRight(trim(node.getRight())); } else if ((node.getLeft()!=null) && (node.getRight()==null)) { node.setLeft(trim(node.getLeft())); } else { // this is done when // ((node.getLeft()!=null) && (node.getRight()!=null)) node.setLeft(trim(node.getLeft())); node.setRight(trim(node.getRight())); } return node; } }