[프로그래머스] 롤케이크 자르기 java풀이 (LEVEL2)

https://school.programmers.co.kr/learn/courses/30/lessons/132265

프로그래머스

나의풀이

import java.util.*;
class Solution {
    public int solution(int[] topping) {
        int answer = 0;
        Map<Integer, Integer> s1 = new HashMap<>();
        Map<Integer, Integer> s2 = new HashMap<>();
        
        s1.put(topping[0], 1);
        for(int i=1; i<topping.length; i++){
            s2.put(topping[i], s2.getOrDefault(topping[i], 0)+1);
        }
        
        if(s1.size() == s2.size()){
            answer++;
        }
        
        for(int i=1; i<topping.length-1; i++){
            s1.put(topping[i], s1.getOrDefault(topping[i], 0)+1);
            if(s2.getOrDefault(topping[i], 0) > 1){
                s2.put(topping[i], s2.getOrDefault(topping[i], 0)-1);
            }else{
                s2.remove(topping[i]);
            }

          if(s1.size() == s2.size()){
            answer++;
            }
        }
        
        return answer;
    }
}