[Java/백준/스택] 10828 - 스택

문제

https://www.acmicpc.net/problem/10828

10828번: 스택

 

코드

내장 Stack 사용

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Stack;

public class Main{
	public static void main(String[] args) throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		
		int N = Integer.parseInt(br.readLine());
		Stack<String> stack = new Stack<>();
		
		for(int i=0; i<N; i++) {
			String[] str = br.readLine().split("\\s");
			
			if(str[0].equals("push")) {
				stack.push(str[1]);
			}else if(str[0].equals("pop")) {
				if(!stack.isEmpty())
					System.out.println(stack.pop());
				else
					System.out.println(-1);
			}else if(str[0].equals("top")) {
				if(!stack.isEmpty())
					System.out.println(stack.peek());
				else
					System.out.println(-1);
			}else if(str[0].equals("size")) {
				System.out.println(stack.size());
			}else if(str[0].equals("empty")) {
				if(!stack.isEmpty())
					System.out.println(0);
				else
					System.out.println(1);
			}
		}
	}	
}