[code]class Solution { public List levelOrder(TreeNode root) { List result = new ArrayList(); if (root == null) { return result; } // TreeNode index=root; Queue queue = new LinkedList(); //用来判断遍历终止的条件 int judge = 1; queue.add(root); while (judge != 0) { int size = queue.size(); //用来判断遍历终止的条件 int xiao = 0; List list = new ArrayList(); for (int i = 1; i