# Delete Nodes And Return Forest

Given the root of a binary tree, each node in the tree has a distinct value.

After deleting all nodes with a value in to_delete, we are left with a forest (a disjoint union of trees).

Return the roots of the trees in the remaining forest.  You may return the result in any order.

Example 1:

Input: root = [1,2,3,4,5,6,7], to_delete = [3,5]
Output: [[1,2,null,4],[6],[7]]

Constraints:

• The number of nodes in the given tree is at most 1000.
• Each node has a distinct value between 1 and 1000.
• to_delete.length <= 1000
• to_delete contains distinct values between 1 and 1000.
# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
def delNodes(self, root, to_delete):
"""
:type root: TreeNode
:type to_delete: List[int]
:rtype: List[TreeNode]
"""
self.forests = []
self.delete = to_delete

node = self.divideAndConquer(root)

if node:
self.forests.append(node)

return self.forests

def divideAndConquer(self, node):

if not node:
return None

left = self.divideAndConquer(node.left)
right = self.divideAndConquer(node.right)

if node.val not in self.delete:
node.left = left
node.right = right
return node
else:
if left:
self.forests.append(left)
if right:
self.forests.append(right)

return None