AcWing828.模拟栈
import java.util.Scanner;public class Main{public static void main(String[] args) {Scanner sc = new Scanner(System.in);int[] stl = new int[100010];//栈int m = sc.nextInt();//输入次数int tt = 0;//栈顶while (m-- > 0){String s = sc.next();if (s.equals("push")){int x = sc.nextInt();stl[++tt] = x;} else if (s.equals("pop")){tt--;} else if (s.equals("empty")){if (tt > 0){System.out.println("NO");} else {System.out.println("YES");}} else {System.out.println(stl[tt]);}}}
}