__helper(root.right, l+1)
__helper(root, 0)
def right_view(root, h):
visited = [0]*h
def __helper(root, l):
if not root:
return
if not visited[l]:
print(root.val, end=" ")
visited[l] = 1
__helper(root.right, l+1)
__helper(root.left, l+1)
__helper(root, 0)
t = BinaryTree()
t.build([1,2,3,None,5,None,4])
print("Left: ", end=" ")
left_view(t.root, t.height())
print("\nRight: ", end=" ")
right_view(t.root, t.height())
