[leetcode]102 Binary Tree level Order traversal

https://oj.leetcode.com/problems/binary-tree-level-order-traversal/

http://blog.csdn.net/linhuanmars/article/details/23404111

/** * definition for binary tree * public class treenode {  *     int val; *     TreeNode left;  *     treenode right; *     treenode (int &NBSP;X)  { val = x; } * } */public class solution {     public list<list<integer>> levelorder (TreeNode root)  {                 // this  is how we use queue to iterate a tree.         // To let nodes on the same level be  returned in the same list, we can store an extra level  for each nodes.                list<list< Integer>> result = new arraylist<> ();         if  (root == null)              return result;        queue<nodewithlevel> queue  = new LinkedList<> ();         queue.offer (new  nodewithlevel (root, 0));        while  (!queue.isEmpty ( ))         {             nodewithlevel nodewithlevel = queue.poll ();             if  (Nodewithlevel.level == result.size ())         &nbSp;        result.add (new arraylist<integer> ());             result.get (NodeWithLevel.level). Add ( NodeWithLevel.node.val);                         if  (nodewithlevel.node.left != null )             {                 queue.offer (New nodewithlevel ( nodewithlevel.node.left, nodewithlevel.level + 1));             }            if   (Nodewithlevel.node.right != null)              {     &nbsP;          queue.offer (New nodewithlevel ( nodewithlevel.node.right, nodewithlevel.level + 1));             }        }                 return result;    }         private static class NodeWithLevel     {        TreeNode node;         int level;        nodewithlevel (TreeNode  Node, int level)         {             this.node = node;             this.level = level;        }    }} 

[leetcode]102 Binary Tree level Order traversal