#Leet Code# Populating Next Right Pointers in Each Node II

描述：注意需要先self.connect(right)再self.connect(left)，否则会有case通不过，原因是左边递归执行时依赖与右边的next已经建立，而先执行connect(left)的话右边还没有完成关系的建立。

代码：

 class Solution:
     # @param root, a tree node
     # @return nothing
     def doSth(self, nextNode, conNode):
         while nextNode is not None:
             if nextNode.left is None and nextNode.right is None:
                 nextNode = nextNode.next
             elif nextNode.left is not None:
                 conNode.next = nextNode.left
                 break
             else:
                 conNode.next = nextNode.right
                 break

     def connect(self, root):
         if root is None:
             return

         if root.left is None and root.right is None:
             return
         elif root.left is None and root.right is not None:
             self.doSth(root.next, root.right)
         elif root.left is not None and root.right is None:
             self.doSth(root.next, root.left)
         else:
             root.left.next = root.right
             self.doSth(root.next, root.right)

         self.connect(root.right)
         self.connect(root.left)