[Java / 코딩테스트] 겹쳐진 압축 해제

 

1. 생각

• 전형적인 스택 문제
• ")"까지 보고 반복문

 

 

2. 코드

import java.util.*;
class Solution {
    public String solution(String s){
        String answer = "";
        Stack<String> st = new Stack<>();
        for (char c : s.toCharArray()) {
            if(c == ')') {
                String tmp = "";
                while (!st.empty()) {
                    String t = st.pop();
                    if(t.equals("(")) {
                        String num = "";
                        while (!st.empty() && Character.isDigit(st.peek().charAt(0))) {
                            num = st.pop() + num;
                        }
                        String res = "";
                        int cnt = 0;
                        if(num.equals("")) cnt = 1;
                        else cnt = Integer.parseInt(num);
                        for (int i = 0; i < cnt; i++) {
                            res += tmp;
                        }
                        st.push(res);
                        break;
                    } else {
                        tmp = t + tmp;
                    }
                }
            } else {
                st.push(String.valueOf(c));
            }
        }
        for(String x : st) {
            answer += x;
        }
        return answer;
    }

    public static void main(String[] args){
        Solution T = new Solution();
        System.out.println(T.solution("3(a2(b))ef"));
        System.out.println(T.solution("2(ab)k3(bc)"));
        System.out.println(T.solution("2(ab3((cd)))"));
        System.out.println(T.solution("2(2(ab)3(2(ac)))"));
        System.out.println(T.solution("3(ab2(sg))"));
    }
}

 

[결과]

abbabbabbef
ababkbcbcbc
abcdcdcdabcdcdcd
ababacacacacacacababacacacacacac
absgsgabsgsgabsgsg