LIFO인 선형리스트의 일종
https://velog.io/@eoveol/Algorithm-%EC%8A%A4%ED%83%9D-1
https://docs.oracle.com/javase/8/docs/api/java/util/Stack.html
java.util.Stack<E>
A more complete and consistent set of LIFO stack operations is provided by the Deque interface and its implementations, which should be used in preference to this class. For example:
Deque<Integer> stack = new ArrayDeque<Integer>();
empty()
peek()
pop()
push(E item)
search(Object o)