leetcode1305

 1 class Solution:
 2     def midOrder(self,root,l):
 3         if root != None:
 4             if root.left != None:
 5                 self.midOrder(root.left,l)
 6             l.append(root.val)
 7             if root.right != None:
 8                 self.midOrder(root.right,l)
 9                 
10     def getAllElements(self, root1: TreeNode, root2: TreeNode) -> List[int]:
11         l1,l2 = [],[]
12         self.midOrder(root1,l1)
13         self.midOrder(root2,l2)
14         res = []
15         n1,n2 = len(l1),len(l2)
16         i,j = 0,0
17         while i < n1 and j < n2:
18             if l1[i] <= l2[j]:
19                 res.append(l1[i])
20                 i += 1
21             else:
22                 res.append(l2[j])
23                 j += 1
24         if i < n1:
25             res += l1[i:]
26         elif j < n2:
27             res += l2[j:]
28         return res

分别使用中序遍历两颗二叉搜索树，得到两个有序列表。再将两个数组合并为一个有序数组。