topic
二叉树按层打印和ZigZag打印
java code
package com.lizhouwei.chapter3;
import java.util.LinkedList;
import java.util.Queue;
/**
* @Description:二叉树按层打印和ZigZag打印
* @Author: lizhouwei
* @CreateDate: 2018/4/14 21:47
* @Modify by:
* @ModifyDate:
*/
public class Chapter3_9 {
public void levelPrint(Node head){
if(head==null){
return;
}
Queue<Node> queue = new LinkedList<Node>();
queue.offer(head);
System.out.print("level1:");
Node nlast =null;
Node last=head;
int level= 1;
while (!queue.isEmpty()){
head = queue.poll();
System.out.print(head.value+" ");
if(head.left!=null){
queue.offer(head.left);
nlast = head.left;
}
if(head.right!=null){
queue.offer(head.right);
nlast = head.right;
}
if(last ==head&& !queue.isEmpty()){
last = nlast;
System.out.println();
System.out.print("level"+(++level)+":");
}
}
}
public void zigZagPrint(Node head){
if (head==null){return;}
LinkedList<Node> dqueue = new LinkedList<Node>();
dqueue.offerFirst(head);
boolean lr = true;
Node nlast =null;
Node last=head;
int level=1;
System.out.print("level1:");
while (!dqueue.isEmpty()){
if(lr){
head =dqueue.pollFirst();
if(head.left!=null){
dqueue.offerLast(head.left);
nlast= nlast==null? head.left:nlast;
}
if(head.right!=null){
dqueue.offerLast(head.right);
nlast= nlast==null? head.right:nlast;
}
}else{
head =dqueue.pollLast();
if(head.right!=null){
dqueue.offerFirst(head.right);
nlast= nlast==null?head.right:nlast;
}
if(head.left!=null){
dqueue.offerFirst(head.left);
nlast= nlast==null?head.left:nlast;
}
}
System.out.print(head.value+" ");
if(last==head && !dqueue.isEmpty()){
last =nlast;
nlast =null;
lr =!lr;
System.out.println();
System.out.print("level"+(++level)+":");
}
}
}
//测试
public static void main(String[] args) {
Chapter3_9 chapter = new Chapter3_9();
int[] arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
Node head = NodeUtil.generTree(arr, 0, arr.length - 1);
System.out.println("层打印");
chapter.levelPrint(head);
System.out.println("\n");
System.out.println("ZigZag打印");
chapter.zigZagPrint(head);
}
}
result