名企面试100题_16
输入一颗二元树，从上往下按层打印树的每个结点，同一层中按照从左往右的顺序打印。

public static void hierarchyTraverse(BinaryTree tree){Queue queue = new Queue();if(tree.getRoot() != null){queue.enQueue(tree.getRoot());while(!queue.emptyStack()){TreeNode p = queue.deQueue();System.out.print(p.getVlaue() + " ");if(p.left != null){queue.enQueue(p.left);}if(p.right!=null){queue.enQueue(p.right);}}}}

package cn.emma.interview_15;import cn.emma.interview_15.BinaryTree.TreeNode;public class Queue {public final static int MAX = 100;private static int head;private static int tail;private static TreeNode[] S = new TreeNode[MAX];public boolean emptyStack(){if(head == tail){return true;}return false;}public static void enQueue(TreeNode x){S[tail++] = x;}public static TreeNode deQueue(){return S[head++];}}