leetcode之Populating Next Right Pointers in Each Node

这题就是在正常的广度优先搜索的栈里面加上了链表指向。比较简单的一道题。代码如下：

# Definition for binary tree with next pointer.# class TreeLinkNode(object):#     def __init__(self, x):#         self.val = x#         self.left = None#         self.right = None#         self.next = Noneclass Solution(object):    def connect(self, root):        """        :type root: TreeLinkNode        :rtype: nothing        """        if not root:            return root         a = [root]        b = []        while a != []:            for i in a:                if i.left:                    b.append(i.left)                if i.right:                    b.append(i.right)            if b != []:                for i in range(len(b) - 1):                    b[i].next = b[i + 1]            a = b            b = []