二叉树的宽度（广度）优先遍历

二叉树的宽度（广度）优先遍历

Java代码如下:

import java.util.LinkedList;
import java.util.Queue;
public class Test1 {
	private static class BTNode{
		public int Data;
		public BTNode Left;
		public BTNode Right;
		public BTNode(int data) {
			Data=data;
			Left=null;
			Right=null;
		}
		public static BTNode CreateBinaryTree() {
			BTNode root=new BTNode(1);
			root.Left=new BTNode(2);
			root.Right=new BTNode(3);
			BTNode p=root.Left;
			p.Left=new BTNode(4);
			p.Right=new BTNode(5);
			p=root.Right;
			p.Right=new BTNode(6);
			return root;
		}
		public static void ShowBinaryTree(BTNode root) {
			if(root==null) {
				System.out.println("This Binary tree is empty!");
				return;
			}
			int sum=0;//The total nodes
			Queue<BTNode> q=new LinkedList<BTNode>();
			q.add(root);
			int next=0;//Next level's nodes
			int count=1;//This level's nodes
			while(!q.isEmpty()) {
				if(count==0) {//This level's nodes has been printed 
					count=next;
					next=0;//reset next nodes
				}
				BTNode p=q.poll();
				count--;
				sum++;
				System.out.print(p.Data);
				if(p.Left!=null) {
					q.add(p.Left);
					next++;
				}
				if(p.Right!=null) {
					q.add(p.Right);
					next++;
				}
				if(count==0)System.out.println();
				else System.out.print(" ");
			}
			System.out.println(sum);
		}
	}
	public static void main(String[] args) {
		BTNode Root=BTNode.CreateBinaryTree();
		BTNode.ShowBinaryTree(Root);
	}
}

运行结果如下：