二叉树的递归套路——满二叉树

package com.harrison.class08;
public class Code05_IsFull {
  public static class Node {
    public int value;
    public Node left;
    public Node right;
    public Node(int data) {
      this.value = data;
    }
  }
  public static class Info{
    public int height;
    public int nodes;
    public Info(int h,int n) {
      height=h;
      nodes=n;
    }
  }
  public static Info process1(Node head) {
    if(head==null) {
      return new Info(0, 0);
    }
    Info leftInfo=process1(head.left);
    Info righInfo=process1(head.right);
    int height=Math.max(leftInfo.height, righInfo.height)+1;
    int nodes=leftInfo.nodes+righInfo.nodes+1;
    return new Info(height, nodes);
  }
  public static boolean isFull1(Node head) {
    if(head==null) {
      return true;
    }
    Info allInfo=process1(head);
    return (1<<allInfo.height)-1==allInfo.nodes;
  }
  public static int h(Node head) {
    if (head == null) {
      return 0;
    }
    return Math.max(h(head.left), h(head.right)) + 1;
  }
  public static int n(Node head) {
    if (head == null) {
      return 0;
    }
    return n(head.left) + n(head.right) + 1;
  }
  public static boolean isFull2(Node head) {
    if (head == null) {
      return true;
    }
    int height = h(head);
    int nodes = n(head);
    return (1 << height) - 1 == nodes;
  }
  public static Node generateRandomBST(int maxLevel, int maxValue) {
    return generate(1, maxLevel, maxValue);
  }
  public static Node generate(int level, int maxLevel, int maxValue) {
    if (level > maxLevel || Math.random() < 0.5) {
      return null;
    }
    Node head = new Node((int) (Math.random() * maxValue));
    head.left = generate(level + 1, maxLevel, maxValue);
    head.right = generate(level + 1, maxLevel, maxValue);
    return head;
  }
  public static void main(String[] args) {
    int maxLevel = 5;
    int maxValue = 100;
    int testTimes = 1000000;
    for (int i = 0; i < testTimes; i++) {
      Node head = generateRandomBST(maxLevel, maxValue);
      if (isFull1(head) != isFull2(head)) {
        System.out.println("Oops!");
      }
    }
    System.out.println("finish!");
  }
}