# class MinStack(object):
# def __init__(self):
# """
# initialize your data structure here.
# """
# self.stack = []
# self.min_stack = []
# def push(self, x):
# """
# :type x: int
# :rtype: nothing
# """
# self.stack.append(x)
# if len(self.min_stack) == 0 or x <= self.min_stack[-1]:
# self.min_stack.append(x)
# def pop(self):
# """
# :rtype: nothing
# """
# if len(self.stack) > 0:
# last = self.stack[-1]
# # Need to check whether pop minStack
# if len(self.min_stack) > 0 and last == self.min_stack[-1]:
# self.min_stack.pop()
# self.stack.pop()
# def top(self):
# """
# :rtype: int
# """
# if len(self.stack) > 0:
# return self.stack[-1]
# return None
# def getMin(self):
# """
# :rtype: int
# """
# if len(self.min_stack) > 0:
# return self.min_stack[-1]
# else:
# if len(self.stack) > 0:
# return self.stack[-1]
# return None
class MinStack(object):
def __init__(self):
"""
initialize your data structure here.
"""
self.stack = []
self.min_stack = []
def push(self, x):
"""
:type x: int
:rtype: nothing
"""
self.stack.append(x)
if len(self.min_stack) == 0:
self.min_stack.append(x)
return
if x <= self.min_stack[-1]:
self.min_stack.append(x)
else:
# Push top of min stack again
self.min_stack.append(self.min_stack[-1])
def pop(self):
"""
:rtype: nothing
"""
if len(self.stack) > 0:
# Much simple than solution 1
# But use more space
self.min_stack.pop()
self.stack.pop()
def top(self):
"""
:rtype: int
"""
if len(self.stack) > 0:
return self.stack[-1]
return None
def getMin(self):
"""
:rtype: int
"""
if len(self.min_stack) > 0:
return self.min_stack[-1]
return None
