Leetcode Binary Tree level Order traversal

Given a binary tree, return the level order traversal of its nodes ' values. (ie, from left-to-right, level by level).

For example:
Given binary Tree {3,9,20,#,#,15,7} ,

    3   /   9    /   7

Return its level order traversal as:

[  3],  [9,20],  [15,7]]

Confused what "{1,#,2,3}" means? > read more on how binary tree is serialized on OJ.

OJ ' s Binary Tree serialization:

The serialization of a binary tree follows a level order traversal, where ' # ' signifies a path terminator where no node ex Ists below.

Here's an example:

   1  /  2   3    /   4         5

The above binary tree is serialized as "{1,2,3,#,#,4,#,#,5}". Test instructions: The hierarchical traversal of the tree.

Idea: The use of the queue to deal with the line, each record is queued to a few, is the next level to access the

/** * Definition for Binary tree * public class TreeNode {* int val, * TreeNode left, * TreeNode right; TreeNode (int x) {val = x;} *} */public class Solution {public list<list<integer>> levelorder (TreeNode ro    OT) {list<list<integer>> result = new arraylist<list<integer>> ();    Result.clear ();        if (root = null) return result;    linkedlist<treenode> q = new linkedlist<treenode> ();    Q.add (root);    int level = 0, count = 1;    while (!q.isempty ()) {list<integer> tmp = new arraylist<integer> ();    Tmp.clear ();    level = 0;    for (int i = 0; i < count; i++) {root = Q.pollfirst ();    Tmp.add (Root.val);    if (root.left! = null) {Q.add (root.left);    ++level;    } if (root.right! = null) {Q.add (root.right);    ++level;    }} count = level;    Result.add (TMP);    } return result; }}

Leetcode Binary Tree level Order traversal