Method pop

Target Offer/用两个栈实现队列.py:12–18

(self)

    def push(self, node):
        self.stack1.append(node)
    def pop(self):
        if len(self.stack2) == 0 and len(self.stack1) == 0:
            return
        elif len(self.stack2) == 0:
            while len(self.stack1) > 0:
                self.stack2.append(self.stack1.pop())
        return self.stack2.pop()

P = Solution()
P.push(10)