def preorder_visit_no_recruse(node):
current = node
s = Stack()
while current or not s.is_empty():
if current:
current.echo()
if current.right:
s.push(current.right)
if current.left:
current = current.left
else:
current = None
else:
current = s.pop()
def _compute_block_id(self, block):
""" For every block build a Cartesian tree using stack-based approach.
During the build process encode stack pushes as *1* and stack pops as *0*.
The generated 2b-bit number is the id of the block.
@param block (List[int]): An array of integer numbers.
@return code (int): A 2b-bit integer giving the id of the block,
where b is the size of the block.
"""
binary_code = [0] * (2 * len(block))
idx = 0
S = Stack()
for i in range(len(block)):
while (not S.is_empty()) and (S.top() > block[i]):
S.pop()
idx += 1
S.push(block[i])
binary_code[idx] = 1
idx += 1
code = "".join(str(bit) for bit in binary_code)
return int(code, 2)