programmers_[3차] 파일명 정렬_java

https://school.programmers.co.kr/learn/courses/30/lessons/17686

프로그래머스

import java.util.*;

class Solution {
    public String[] solution(String[] files) {
        int filesLength = files.length;
        
        String[] answer = new String[filesLength];
        
        PriorityQueue<FileName> pq = new PriorityQueue<>();
        
        
        for(int i = 0; i<filesLength; i++){
            String[] file = splitFile(files[i]);
            pq.offer(new FileName(files[i],file[0], file[1], file[2], i));
        }
        
        int idx = 0;
        while(!pq.isEmpty()){
            FileName now = pq.poll();
            answer[idx++] = now.original;
        }
        
        return answer;
    }
    
    public String[] splitFile(String file){
        String[] splitFile = new String[3];
        
        int fileLength = file.length();
        int tailStartIdx = fileLength;
        int numberStartIdx = 0;
        for(int i = 0; i<fileLength; i++){
            if(numberStartIdx == 0 && ('0' <= file.charAt(i) && file.charAt(i) <= '9') ){// numberStartIdx 찾기
                numberStartIdx = i;
            }            
            else if(numberStartIdx != 0 && ('0' > file.charAt(i) || file.charAt(i)  > '9')){ //tailStartIdx 찾기 
                tailStartIdx = i;
                break;
            }  
        }
        splitFile[0] = file.substring(0, numberStartIdx);
        splitFile[1] = file.substring(numberStartIdx, tailStartIdx);
        splitFile[2] = file.substring(tailStartIdx);
        
        return splitFile;            
    }
    
    public class FileName implements Comparable<FileName>{
        String head, number, tail, original;
        int idx; // 들어온 순서
        
        public FileName(String original, String head, String number, String tail, int idx){
            this.original = original;
            this.head = head.toLowerCase();
            this.number = number;
            this.tail = tail.toLowerCase();
            this.idx = idx;
        }
        
        @Override
        public int compareTo(FileName o){
            if(head.compareTo(o.head) > 0){
                return 1;
            }else if(head.compareTo(o.head) < 0){
                return -1;
            }else{
                if(Integer.parseInt(number) - Integer.parseInt(o.number) > 0){
                    return 1;
                }else if(Integer.parseInt(number) - Integer.parseInt(o.number) < 0){
                    return -1;
                }else{
                    return idx - o.idx;
                }
            }
        }
        
        @Override
        public String toString(){
            return " " + head + " " + number + " " + tail + " " + idx + " " + original;
        }
    }
}