class Solution_32b(object):
def __init__(self):
self.queue = LinkedQueue()
def print_tree(self, treeroot):
if treeroot is None:
return
self.queue.add(treeroot)
nextlevel, tobeprinted = 0, 1
print('Print the tree structure by level.')
while not self.queue.isEmpty():
pnode = self.queue.peek()
print('%d' % pnode.data_, end=' | ')
if pnode.left_ is not None:
self.queue.add(pnode.left_)
nextlevel += 1
if pnode.right_ is not None:
self.queue.add(pnode.right_)
nextlevel += 1
self.queue.pop()
tobeprinted -= 1
if tobeprinted == 0:
print('\n')
tobeprinted = nextlevel
nextlevel = 0
class Stack(object):
def __init__(self):
self.stack1 = LinkedQueue()
self.stack2 = LinkedQueue()
def isEmpty(self):
if self.__len__() == 0:
return True
else:
return False
def __len__(self):
if self.stack1.size_ == 0:
return self.stack2.size_
else:
return self.stack1.size_
def peek(self):
if self.isEmpty():
raise KeyError('The stack is empty.')
elif not self.stack1.isEmpty():
item = self.stack1.peek()
return item
else:
item = self.stack2.peek()
return item
def push(self, item):
if self.isEmpty() or (not self.stack1.isEmpty()
and self.stack2.isEmpty()):
self.stack1.add(item)
else:
self.stack2.add(item)
def pop(self):
if self.isEmpty():
raise KeyError('The stack is empty.')
if not self.stack1.isEmpty():
while self.stack1.front_.next is not None:
self.stack2.add(self.stack1.pop())
item = self.stack1.pop()
return item
else:
while self.stack2.front_.next is not None:
self.stack1.add(self.stack2.pop())
item = self.stack2.pop()
return item
# def __iter__(self):
# def travser_stack_recursive(sta, templist):
# if sta.front_.next is not None:
# templist = travser_stack_recursive(sta.front_.next, templist)
# templist.append(sta.front_.data)
# return templist
#
# templist = list()
# if self.isEmpty():
# raise KeyError('The stack is empty.')
#
# if not self.stack1.isEmpty():
# travser_stack_recursive(self.stack1, templist)
# return iter(templist)
# else:
# travser_stack_recursive(self.stack2, templist)
# return iter(templist)
def __iter__(self):
if self.isEmpty():
raise KeyError('The stack is empty.')
templist = list()
if not self.stack1.isEmpty():
tempstack = copy.copy(self.stack1)
while tempstack.front_.next is not None:
templist.append(tempstack.pop())
templist.append(tempstack.pop())
templist.reverse() # ******
return iter(templist)
else:
tempstack = copy.copy(self.stack2)
while tempstack.front_.next is not None:
templist.append(tempstack.pop())
templist.append(tempstack.pop()).reverse()
templist.reverse() # ******
return iter(templist)