MinStack.py

import math
class MinStack:

    def __init__(self):
        """
        initialize your data structure here.
        """
        self.stack = []
        self.min = math.inf

    def push(self, x: int) -> None:
        self.x = x
        self.stack.append(x)
        if(x < self.min):
            self.min = x               
            
    def pop(self) -> None:
        t = self.stack.pop()
        if(t==self.min and len(self.stack)):
            self.min = min(self.stack)   
        elif(t==self.min and not len(self.stack)):
            self.min = math.inf

    def top(self) -> int:
        return self.stack[-1]        

    def getMin(self) -> int:
        return self.min     

# Your MinStack object will be instantiated and called as such:
# obj = MinStack()
# obj.push(x)
# obj.pop()
# param_3 = obj.top()
# param_4 = obj.getMin()