[프로그래머스] 코딩테스트 고득점 Kit - 힙(HEAP) (JAVA)

https://programmers.co.kr/learn/courses/30/lessons/42626

코딩테스트 연습 - 더 맵게

PriorityQueue<Integer> pq = new PriorityQueue<>() : 우선순위큐 선언. 최소힙

PriorityQueue<Integer> pq = new PriorityQueue<>(Collections.reverseOrder()) : 우선순위큐 선언. 최대힙

import java.util.*;

class Solution {
    public int solution(int[] scoville, int K) {
        int answer = 0;
        PriorityQueue<Integer> pq = new PriorityQueue<>();
        for(int i=0; i<scoville.length; i++){
            pq.add(scoville[i]);
        }
        
        while(pq.size()>=2 && pq.peek()<K){
            answer++;
            int a=pq.poll();
            int b = pq.poll();
            pq.add(a+2*b);
        }
        if(pq.peek()<K) answer=-1;
        return answer;
    }
}

https://programmers.co.kr/learn/courses/30/lessons/42627

코딩테스트 연습 - 디스크 컨트롤러

Arrays.sort(int[][] jobs, ((o1,o2)->o1[0]-o2[0]) : 0번째 원소를 기준 오름차순

Arrays.sort(int[][] jobs, ((o1,o2)->o2[0]-o1[0]) : 0번째 원소를 기준 내림차순

import java.util.*;

class Solution {
    public int solution(int[][] jobs) {
        int answer = 0;
        int cnt=0;
        int end=0;
        int i=0;
        Arrays.sort(jobs,((o1,o2)->o1[0]-o2[0])); //첫번째 요소 기준 오름차순
        PriorityQueue<int[]> pq = new PriorityQueue<>((o1,o2)->o1[1]-o2[1]);
  
        while(cnt<jobs.length){
            while(i<jobs.length && end>=jobs[i][0]){
                pq.add(jobs[i++]);
            }
            if(!pq.isEmpty()){
                int[] cur = pq.poll();
                end+=cur[1];
                answer+=end-cur[0];
                // System.out.println(end-cur[0]);
                cnt++;
            }else{
                end=jobs[i][0];
            }
        }
        return answer/jobs.length;
    }
}