Given a binary tree
struct TreeLinkNode { TreeLinkNode *left; TreeLinkNode *right; TreeLinkNode *next; }
Populate each next pointer to point to its next right node. If there is no next right node, the next pointer should be set to NULL
.
Initially, all next pointers are set to NULL
.
Note:
- You may only use constant extra space.
- You may assume that it is a perfect binary tree (ie, all leaves are at the same level, and every parent has two children).
For example,
Given the following perfect binary tree,
1 / 2 3 / / 4 5 6 7
After calling your function, the tree should look like:
1 -> NULL / 2 -> 3 -> NULL / / 4->5->6->7 -> NULL
注意:
1, 题目种假设是perfect binary tree
设置两个变量,分别用来纪录行和列
# Definition for binary tree with next pointer. # class TreeLinkNode: # def __init__(self, x): # self.val = x # self.left = None # self.right = None # self.next = None class Solution: # @param root, a tree link node # @return nothing def connect(self, root): if root==None: return row=root while row.left!=None: col=row while col!=None: col.left.next=col.right if col.next!=None: col.right.next=col.next.left col=col.next row=row.left