[프로그래머스] 택배상자 java 풀이 (LEVEL2)

https://school.programmers.co.kr/learn/courses/30/lessons/131704

프로그래머스

 

import java.util.*;
class Solution {
    public int solution(int[] order) {
        int answer = 0;
        Stack<Integer> s= new Stack<>();
        
        int idx=0;
        int temp=order[idx];
        for(int i=1; i<=order.length; i++){
            if(i != temp){
                if(s.size() >0 && s.peek() == temp){
                    s.pop();
                    answer++;
                    temp=order[++idx];
                    i--;
                    continue;
                }
                s.push(i);
            }else{
                answer++;
                temp=order[++idx];
            }
        }
        while(!s.isEmpty()){
            if(s.peek() == temp){
                answer++;
                s.pop();
                if(idx+1>=order.length){
                    break;
                }
                temp=order[++idx];
            }else{
                break;
            }
        }        
        return answer;
    }
}