def sort(self):
r = Stack()
while not self.isEmpty():
# insert each element in s in sorted order into r
tmp = self.pop()
while not r.isEmpty() and r.peek() > tmp:
self.push(r.pop())
r.push(tmp)
# copy the elements from r back into s
while not r.isEmpty():
self.push(r.pop())
def __init__(self):
self.stack_newest = Stack()
self.stack_oldest = Stack()
class MyQueue:
def __init__(self):
self.stack_newest = Stack()
self.stack_oldest = Stack()
def size(self):
return self.stack_newest.size() + self.stack_oldest.size()
def add(self, value):
#push onto stack_newest which always has newest elements on top
self.stack_newest.push(value)
#move elements from stack_newest into stack_oldest. This is usually done so that
#we can do operations on stack_oldest
def shift_stacks(self):
if(self.stack_oldest.isEmpty()):
while(not self.stack_newest.isEmpty()):
self.stack_oldest.push(self.stack_newest.pop())
def peek(self):
self.shift_stacks() #ensure stack_oldest has the current elements
return self.stack_oldest.peek() #retrieve the oldest elements
def remove(self):
self.shift_stacks()#ensure stack_oldest has the current elements
return self.stack_oldest.pop() #pop the oldest elements
def __str__(self):
out ="Newer: " + str(self.stack_newest.items ) + " " + "Older: " + str( self.stack_oldest.items )
return out
