def spt_height(spt: SimplePrefixTree) -> int:
"""Return the height of the spt
Precondition: spt is not an empty SimplePrefixTree
"""
if spt.is_leaf(): # an internal node with only 1 leaf
return 1
else:
# spt is not a leaf
count = 1
for subtree in spt.subtrees:
height = spt_height(subtree)
if height >= count:
count = height + 1 # + 1 including the own tree
return count
def num_nodes(spt: SimplePrefixTree) -> int:
"""Return the number of nodes an SPT has
>>> spt = SimplePrefixTree('sum')
>>> spt.insert('x', 1, ['x'])
>>> num_nodes(spt)
3
>>> spt.insert('che', 3,['c','h','e'])
>>> num_nodes(spt)
7
>>> spt.insert('xenon', 2, ['x','e','n','o','n'])
>>> num_nodes(spt)
12
"""
if spt.weight == 0:
return 1
elif spt.is_leaf():
return 1
else:
# it's an internal node
count = 1
for subtree in spt.subtrees:
count += num_nodes(subtree)
return count
