题目

image.png

思路

  1. """
  2. # Definition for a Node.
  3. class Node:
  4.     def __init__(self, val: int = 0, left: 'Node' = None, right: 'Node' = None, next: 'Node' = None):
  5.         self.val = val
  6.         self.left = left
  7.         self.right = right
  8.         self.next = next
  9. """
  11. class Solution:
  12.     def connect(self, root: 'Node') -> 'Node':
  13.         if root is None: return root
  14.         queue = [root]
  15.         while len(queue) > 0:
  16.             size = len(queue)
  17.             for i in range(size):
  18.                 node = queue.pop(0)
  19.                 if i < size - 1:
  20.                     node.next = queue[0]
  21.                 if node.left: queue.append(node.left)
  22.                 if node.right: queue.append(node.right)
  23.         return root