def main():
t = Node(10)
t.left = Node(2)
t.left.left = Node(1)
t.left.right = Node(3)
t.right = Node(20)
t.right.right = Node(40)
x = tree_to_linked_list(t)
print x
def _ordered_array_to_node(self, arr, start, end):
# Start cannot be greater than end
if start > end:
return None
mid = (start + end) / 2
root = Node(arr[mid])
# Populate the node structure
root.left = self._ordered_array_to_node(arr, start, mid - 1)
root.right = self._ordered_array_to_node(arr, mid + 1, end)
return root