# leetcode-225

2020年3月23日

### 225. 用队列实现栈

题目

注意栈是 FILO(First In Last Out)，Python 的 list 是 FIFO(First In First Out)。

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    class MyStack:

      def __init__(self):
        """
        Initialize your data structure here.
        """
        self.data = []

      def push(self, x: int) -> None:
        """
        Push element x onto stack.
        """
        self.data.append(x)
        return

      def pop(self) -> int:
        """
        Removes the element on top of the stack and returns that element.
        """
        return self.data.pop(-1)

      def top(self) -> int:
        """
        Get the top element.
        """
        return self.data[-1]

      def empty(self) -> bool:
        """
        Returns whether the stack is empty.
        """
        return not bool(self.data)

    # Your MyStack object will be instantiated and called as such:
    # obj = MyStack()
    # obj.push(x)
    # param_2 = obj.pop()
    # param_3 = obj.top()
    # param_4 = obj.empty()

    #24 ms	13.5 MB