10773 제로

10773번: 제로 (acmicpc.net)

10773번: 제로

package String;

import java.util.Scanner;
import java.util.Stack;

public class Baekjoon_10773_제로 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int K = sc.nextInt();
		Stack<Integer> stack = new Stack<>();
		
		for(int i = 0; i < K; i++) {
			int a = sc.nextInt();
			if(a == 0) 
				stack.pop();
			else
				stack.add(a);
		}
		int result = 0;
		while(stack.size() != 0) {
			result += stack.pop();
		}
		
		System.out.println(result);
		
	}

}