백준 10773번

원본 : www.acmicpc.net/problem/10773

10773번: 제로

 

풀이

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.Stack;

public class Main {

	public static BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
	public static BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(System.out));

	public static void main(String[] args) throws Exception {
		int n = Integer.parseInt(reader.readLine());
		
		Stack<Integer> stack = new Stack<>();
		
		for (int i = 0; i < n; i++) {
			int m = Integer.parseInt(reader.readLine());
			if (m == 0) {
				stack.pop();
			} else {
				stack.add(m);
			}
		}
		
		int sum = 0;
		while (true) {
			if (stack.isEmpty()) {
				break;
			} else {
				sum += stack.pop();
			}
		}
		
		writer.write(sum + "");
		writer.flush();
	}
	
}