[백준][Java] 10828번 스택

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import java.util.*; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int N = sc.nextInt(); sc.nextLine(); Stack<Integer> stack = new Stack<>(); while(sc.hasNext()) { String s = sc.next(); if(s.equals("push")) { stack.push(sc.nextInt()); } else if(s.equals("top")) { if(stack.isEmpty()) System.out.println("-1"); else System.out.println(stack.peek()); } else if(s.equals("size")) { System.out.println(stack.size()); } else if(s.equals("empty")) { if(stack.isEmpty()) System.out.println("1"); else System.out.println("0"); } else if(s.equals("pop")) { if(stack.isEmpty()) System.out.println("-1"); else System.out.println(stack.pop()); } } } }