import java.util.*;
public class BinaryTree {
protected Node root;
public BinaryTree(Node root) {
this.root = root;
}
public Node getRoot() {
return root;
}
/** 构造树 */
public static Node init() {
Node a = new Node('A');
Node b = new Node('B', null, a);
Node c = new Node('C');
Node d = new Node('D', b, c);
Node e = new Node('E');
Node f = new Node('F', e, null);
Node g = new Node('G', null, f);
Node h = new Node('H', d, g);
return h;// root
}
/**
* 返回树的层数
*
* @param p
* @return
*/
public static int h(Node p) {
if (p == null)
return -1;
return 1 + Math.max(h(p.getLeft()), h(p.getRight()));// 返回较大的
}
/**
* 检查是否是平衡树
*
* @param p
* @return
*/
public static boolean checkAVL(Node p) {
if (p == null)
return true;
// 左子树与右子树绝对值不能超过 1,并且左右子树也是平衡二叉树
return (Math.abs(h(p.getLeft()) - h(p.getRight())) <= 1 && checkAVL(p.getLeft()) && checkAVL(p.getRight()));
}
/**
* @param args
*/
public static void main(String[] args) {
BinaryTree tree = new BinaryTree(init());
System.out.println("是否是平衡树");
System.out.println(checkAVL(tree.getRoot()));
}
}
class Node {
private char key;
private Node left, right;
public Node(char key) {
this(key, null, null);
}
public Node(char key, Node left, Node right) {
this.key = key;
this.left = left;
this.right = right;
}
public char getKey() {
return key;
}
public void setKey(char key) {
this.key = key;
}
public Node getLeft() {
return left;
}
public void setLeft(Node left) {
this.left = left;
}
public Node getRight() {
return right;
}
public void setRight(Node right) {
this.right = right;
}
}
C:\ex>java BinaryTree
是否是平衡树
false
[img]http://dl.iteye.com/upload/attachment/0072/3033/114e5346-bf3e-3bf5-b696-7bfbf260a382.gif[/img]