def size(n):
sz = 0
if n:
if not hasattr(n, "size"):
if is_leaf(n): n.size = 1
else:
n.size = size(n.left) + 1 + size(n.right)
sz = n.size
return sz
def pop_leaf(node):
"""
pop last added leaf.
pop_leaf(heap) -> (new_heap, poped_node)
"""
if is_leaf(node):
return None, node
if is_pop_from_left(node):
child = left(node)
set_fun = set_left
else:
child = right(node)
set_fun = set_right
if is_leaf(child):
node = set_fun(node, None)
return (node, child)
else:
child, poped = pop_leaf(child)
node = set_fun(node, child)
return (node, poped)