백준 10773 : 제로 _ 자바 java

https://www.acmicpc.net/problem/10773

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import java.io.*;
import java.util.*;

public class Main {

	
    public static void main(String[] args) throws IOException{
    
    	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    	int n= Integer.parseInt(br.readLine());
    	int total=0;
    	Stack<Integer> st = new Stack<>();
    	
    	for(int i=0;i<n;i++) {
    		int a= Integer.parseInt(br.readLine());
    		if(a==0)
    			st.pop();
    		else
    			st.push(a);
    	}
    	
    	while(!st.isEmpty()) {
    		total+=st.peek();
    		st.pop();
    	}
    	
    	System.out.println(total);
    		
    }
    
}