（树）剑指Offer--之字形打印二叉树

import java.util.ArrayList;

/*
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
import java.util.*;
public class Solution {
    public ArrayList<ArrayList<Integer> > Print(TreeNode pRoot) {
        ArrayList<ArrayList<Integer>> result = new ArrayList<ArrayList<Integer>>();
        if(null==pRoot)
            return result;
        Queue<TreeNode> queue = new LinkedList<TreeNode>();
        queue.offer(pRoot);
        ArrayList<Integer> arr = new ArrayList<Integer>();
        boolean isoushu = false;
        while(!queue.isEmpty()){
            int size = queue.size();
            for(int i=0;i<size;i++){
                TreeNode temp = queue.poll();
                arr.add(temp.val);
                if(temp.left!=null)
                    queue.offer(temp.left);
                if(temp.right!=null)
                    queue.offer(temp.right);
            }
            if(isoushu){
              Collections.reverse(arr);   
              isoushu=!isoushu;
            }
            result.add(arr);
            arr= new ArrayList<Integer>();
        }
        return result;    
    }

}