二叉树的按层遍历

package com.harrison.class07;
import java.util.LinkedList;
import java.util.Queue;
public class Code03_LevelTraversalBT {
  public static class Node{
    public int value;
    public Node left;
    public Node right;
    public Node(int v) {
      value=v;
    }
  }
  public static void level(Node head) {
    if(head==null) {
      return ;
    }
    Queue<Node> queue=new LinkedList<>();
    queue.add(head);
    while(!queue.isEmpty()) {
      Node cur=queue.poll();
      System.out.print(cur.value+" ");
      if(cur.left!=null) {
        queue.add(cur.left);
      }
      if(cur.right!=null) {
        queue.add(cur.right);
      }
    }
  }
  public static void main(String[] args) {
    Node head = new Node(1);
    head.left = new Node(2);
    head.right = new Node(3);
    head.left.left = new Node(4);
    head.left.right = new Node(5);
    head.right.left = new Node(6);
    head.right.right = new Node(7);
    level(head);
    System.out.println("\n========");
  }
}