Min Stack

class MinStack(object):

    def __init__(self):
        """
        initialize your data structure here.
        """
        self.arr=[]
        self.arr_len=0
        self.min_num = 0
        

    def push(self, x):
        """
        :type x: int
        :rtype: void
        """
        self.arr.append(x)
        self.arr_len = self.arr_len + 1
        if self.arr_len == 1:
            self.min_num = x
        else:
            if self.min_num > x:
                self.min_num = x
        

    def pop(self):
        """
        :rtype: void
        """
        if self.arr_len > 0:
            top_v=self.arr[self.arr_len - 1]
            self.arr = self.arr[:self.arr_len-1]
            self.arr_len = self.arr_len - 1
            if self.arr_len == 0:
                self.min_num = 0
            if self.min_num == top_v and self.arr_len > 0:
                self.min_num = self.arr[0]
                for v in self.arr[1:]:
                    if self.min_num > v:
                        self.min_num = v
            
        
        

    def top(self):
        """
        :rtype: int
        """
        if self.arr_len > 0:
            return self.arr[self.arr_len - 1]
        

    def getMin(self):
        """
        :rtype: int
        """
        return self.min_num
        


# 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()