[알고리즘문제풀기] 컨트롤 제트

문제

내가 작성한 정답

class Solution {
    public int solution(String s) {
        int answer = 0;
        String[] ss = s.split(" ");
        for(int i=0; i<ss.length; i++){
            if(ss[i].equals("Z")) answer -= Integer.parseInt(ss[i-1]);
            else answer += Integer.parseInt(ss[i]);
        }
        return answer;
    }
}

import java.util.*;
import java.util.stream.*;

class Solution {
    public int solution(String s) {
        String[] ss = s.split(" ");
        List<Integer> n = new ArrayList<>();
        for(int i=0; i<ss.length; i++){
            if(ss[i].equals("Z")) {
                n.add(i-1);
                n.add(i);
            }
        }        
        return IntStream.range(0, ss.length)
                .filter(i -> !n.contains(i)) 
                .map(i -> Integer.parseInt(ss[i]))
                .sum();

    }
}

다른 사람들의 정답

import java.util.*;

class Solution {
    public int solution(String s) {
        int answer = 0;
        Stack<Integer> stack = new Stack<>();

        for (String w : s.split(" ")) {
            if (w.equals("Z")) {
                stack.pop();
            } else {
                stack.push(Integer.parseInt(w));
            }
        }
        for (int i : stack) {
            answer += i;
        }
        return answer;
    }
}