All Elements in Two Binary Search Trees

Given two binary search trees root1 and root2, return a list containing all the integers from both trees sorted in ascending order.

Example 1:

Input: root1 = [2,1,4], root2 = [1,0,3]
Output: [0,1,1,2,3,4]

Example 2:

Input: root1 = [1,null,8], root2 = [8,1]
Output: [1,1,8,8]

Constraints:

• The number of nodes in each tree is in the range [0, 5000].
• -105 <= Node.val <= 105

SOLUTION:

import heapq

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def getAllElements(self, root1: TreeNode, root2: TreeNode) -> List[int]:
        heap = []
        paths = [root1, root2]
        i = 0
        while i < len(paths):
            curr = paths[i]
            if curr:
                heapq.heappush(heap, curr.val)
                if curr.left:
                    paths.append(curr.left)
                if curr.right:
                    paths.append(curr.right)
            i += 1
        return heapq.nsmallest(len(heap), heap)