Question

#Constructor
def tree(label, branches=[]):
for branch in branches:
assert is_tree(branch)
return [label] + list(branches)

#Selectors
def label(tree):
return tree[0]

def branches(tree):
return tree[1:]

def is_tree(tree):
if type(tree) != list or len(tree) < 1:
return false
return True

def is_leaf(tree):
return not branches(tree)

def print_tree(t, indent=0):
  
print(' ' * indent + str(label(t)))
for b in branches(t):
print_tree(b, indent + 1)

Write a function that takes in a tree and doubles every value. It should return a new tree. You can assume that every item is a number. Using the tree above

def double_tree(t):

    """Return a tree with the square of every element in t

    >>> numbers = tree(1,

                       [tree(2,

                             [tree(3),

                              tree(4)]),

                       tree(5,

                            [tree(6,

                                  [tree(7)]),

                             tree(8)])])

    >>> print_tree(double_tree(numbers))

    2

      4

        6

        8

      10

        12

          14

        16

    """

Answer 1

CODE:

class node: #assuming node contain 3 fields- value, left and right

def_ init_(self, val): this.value = Val this.left= this.right = none

def double_tree(t): #t is the root node of tree if t == none: return #empty tree t.value = 2*t.value #double root value double_tree(t.left) # recursive call on left subtree double_tree(t.right) #recursive call on right subtree