109. Convert-Sorted-List-to-Binary-Search-Tree

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
# 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 sortedListToBST(self, head: Optional[ListNode]) -> Optional[TreeNode]:
        myList = []
        while head:
            myList.append(head.val)
            head = head.next
        
        def buildBST(left, right):
            if left > right:
                return None
            m = (left + right) >> 1
            root = TreeNode(myList[m])
            root.left = buildBST(left,m-1)
            root.right = buildBST(m+1,right)
            return root
        return buildBST(0,len(myList)-1)