Leetcode: Min Stack @Python

Use another stack to keep track of the min value so far.

class MinStack:
    # @param x, an integer
    def __init__(self):
        # the stack it self
        self.A = []
        self.minS=[]
    # @return an integer
    def push(self, x):
        n=len(self.A)
        if n==0:
            self.minS.append(x)
        else:
            lastmin=self.minS[-1]
            if x%lt;=lastmin:
                self.minS.append(x)
        self.A.append(x)
    # @return nothing
    def pop(self):
        if len(self.A)>0 and self.A.pop()==self.minS[-1]:
            self.minS.pop()
    # @return an integer
    def top(self):
        return self.A[-1]
        

    # @return an integer
    def getMin(self):
        return self.minS[-1]