def test_peek():
s = MyStack()
s.push(1)
s.push(2)
assert 2 == s.peek()
s.push(3)
assert 3 == s.peek()
s.pop()
assert 2 == s.peek()
class StackMin:
def __init__(self):
self.sMin = MyStack()
def push(self,data):
if data < self.min():
self.sMin.push(data)
self.push(data)
def pop(self):
val = self.pop()
if val == self.sMin.min():
self.sMin.pop()
return val
def min(self):
return self.sMin.peek()