[백준] 10828 스택 - 스택 + 자료구조 JAVA

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

10828번: 스택

코드설명

스택, 자료구조 문제입니다.

 

stack의 함수들을 사용하여 문제에서 주어진대로 구현하면 되는 문제입니다.

 

코드

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

public class Main {
	public static int N;
	public static Stack<Integer> stack = new Stack<>();
	public static int answer = 0;
    public static void main(String[] args) throws IOException{
    	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    	StringTokenizer st = new StringTokenizer(br.readLine());
    	
    	N = Integer.parseInt(st.nextToken());
    	for(int i=0;i<N;i++) {
    		st = new StringTokenizer(br.readLine());
    		String command = st.nextToken();
    		
    		if(command.equals("push")) {
    			int x = Integer.parseInt(st.nextToken());
    			stack.add(x);
    		}
    		else if(command.equals("top")) {
    			if(stack.isEmpty()) {
    				System.out.println("-1");
    			}else {
    				System.out.println(stack.peek());	
    			}
    			
    		}
    		else if(command.equals("size")) {
    			System.out.println(stack.size());
    		}
    		else if(command.equals("empty")) {
    			if(stack.isEmpty()) {
    				System.out.println(1);
    			}else {
    				System.out.println(0);
    			}
    		}
    		else if(command.equals("pop")) {
    			if(stack.isEmpty()) {
    				System.out.println("-1");
    			}else {
    				System.out.println(stack.pop());	
    			}
    			
    		}
    		
    		
    	}
    	
    }
    public static void printstack() {
    	for(int a : stack) {
    		System.out.print(" "+ a);
    	}
    }
    
    
    
}