/*

* 队列LinkedList完成层序遍历，用end记录每层结点数目

*/

public class Solution {

ArrayList<ArrayList<Integer> > Print(TreeNode pRoot) {

ArrayList<ArrayList<Integer>> result = new ArrayList<ArrayList<Integer>>();

if(pRoot==null)

return result;

ListedList<TreeNode> layer = new LinkedList<TreeNode>();

ArrayList<Integer> layerList = new ArrayList<Integer>();

layer.add(pRoot);

int start =0 ,end=1;

while(!layer.isEmpty())

{

TreeNode p =layer.remove();

layerList.add(p.val);

start++;

if(p.left!=null)

layer.add(p.left);

if(p.right!=null)

layer.add(p.right);

if(start==end)

{

end = layer.size();

start=0;

result.add(layerList);

layerList = new ArrayList<Integer>();

}

}

return result;

}

}