자바 우선순위큐(PriorityQueue)

//오름차순(우선순위가 낮은 숫자 순)
PriorityQueue<Integer> pq = new PriorityQueue<>();

//내림차순(우선순위가 높은 숫자 순)
PriorityQueue<Integer> pqHightest = new PriorityQueue<>(Collections.reverseOrder());

pq.add(1);
pq.offer(2);
pq.add(3);
pq.poll(); // 첫번째 값을 반환하고 제거 비어있다면 null
System.out.println(pq); // [2, 3]

pqHightest.add(1);
pqHightest.add(2);
pqHightest.add(3);
pqHightest.peek(); // 첫번째 값 참조 3
pqHightest.remove(); // 첫번째 값 제거
System.out.println(pqHightest); // [2, 1]

pqHightest.clear(); // 초기화

 

https://school.programmers.co.kr/learn/courses/30/lessons/42626?language=java

프로그래머스

import java.util.*;
class Solution {
    public int solution(int[] scoville, int K) {
        
        PriorityQueue<Integer> q = new PriorityQueue<>();
        for(int i = 0; i < scoville.length; i++)
            q.add(scoville[i]);

        int cnt = 0;
        while(q.size() > 1 && q.peek() < K){
            int weakHot = q.poll();
            int secondWeakHot = q.poll();
            q.add(weakHot + (secondWeakHot * 2));
            cnt++;
        }

        if(q.size() <= 1 && q.peek() < K)
            cnt = -1;

        return cnt;
    }
}

 

2023.07.05 - [Coding Test/programmers] - 더 맵게 (힙)

더 맵게 (힙)