判断一棵树是否是搜索二叉树、判断一棵树是否是完全二叉树

 1 package my_basic.class_4;
 2 
 3 import java.util.Stack;
 4 
 5 import class_04.Code_07_IsBSTAndCBT.Node;
 6 
 7 public class Code_07_IsSBTAndCBT {
 8     public static class Node{
 9         int value;
10         Node left;
11         Node right;
12         public Node(int value) {
13             this.value = value;
14         }
15     }
16 
17     /**判断是否是搜索二叉树
18      * 中序遍历 有序 
19      * @return
20      */
21     public static Boolean isSBT(Node head) {
22         if (head != null) {
23             Stack<Node> stack = new Stack<Node>();
24             int pre = Integer.MIN_VALUE;
25             while (!stack.isEmpty() || head!=null) {
26                 if (head!=null) {
27                     stack.add(head);
28                     head = head.left;
29                 }else {
30                     head = stack.pop();
31 //                    System.out.print(head.value+" ");
32                     if (head.value < pre) {
33                         return false;
34                     }
35                     pre = head.value;
36                     head = head.right;
37                 }
38             }
39         }
40         return true;
41     }
42     
43     public static void main(String[] args) {
44         Node head = new Node(4);
45         head.left = new Node(2);
46         head.right = new Node(6);
47         head.left.left = new Node(1);
48         head.left.right = new Node(3);
49         head.right.left = new Node(5);
50 
51         System.out.println(isSBT(head));
52     }
53 }