[LeetCode- Ch.2 정렬 & 검색] 4. 미팅룸 (+ 2차원 배열 정렬)

https://www.lintcode.com/problem/920/

LintCode 炼码

https://www.acmicpc.net/problem/1931

 

 

끝나는 시간 기준 오름차순 정렬, 끝나는 시간이 같으면 시작 시간 기준 오름차순

import java.util.*;
class Main{
        public static boolean main(String args[]) throws Exception{
            Scanner sc = new Scanner(System.in);
            int N=sc.nextInt();
            int[][] arr =new int[N][2];
            //시작 시간, 끝나는 시간
            for(int i=0;i<N;i++){
                arr[i][0]=sc.nextInt();
                arr[i][1]=sc.nextInt();
            }
            Arrays.sort(arr, (o1, o2) -> {
                if(o1[1] == o2[1]){
                    return Integer.compare(o1[0], o2[0]);
                } else {
                    return Integer.compare(o1[1], o2[1]);
                }
            });
            int cnt=0;
            int end=Integer.MIN_VALUE;
            for(int i=0;i<N;i++){
                if(arr[i][0]>=end){
                    cnt++;
                    end=arr[i][1];
                }
            }
            if(cnt==N){
                return boolean flag=true;
            }
            else return boolean flag=false;
        }
}

---

백준

import java.util.*;
class Main{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        int n=in.nextInt();
        int [][] arr = new int[n][2];
        for(int i=0;i<n;i++){
            arr[i][0]=in.nextInt();
            arr[i][1]=in.nextInt();
        }
        Arrays.sort(arr, (o1, o2)->o1[1]==o2[1]?o1[0]-o2[0]: o1[1]-o2[1]);
        //for(int[] a : arr) System.out.println(a[0]+" "+a[1]);
        System.out.println(Solution(n,arr));
    }
    private static int Solution(int n, int[][] arr){
        int start=0;
        int end=0;
        int cnt=0;
        for(int i=0;i<n;i++){
            if(arr[i][0]>=end){
                cnt++;
                end=arr[i][1];
            }
        }
        return cnt;
    }
}

 

리트코드

package Ch2_sorting_search.Q5;

import java.util.*;
class Main{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        int n=in.nextInt();
        int [][] arr = new int[n][2];
        for(int i=0;i<n;i++){
            arr[i][0]=in.nextInt();
            arr[i][1]=in.nextInt();
        }
        Arrays.sort(arr, (o1, o2)->o1[1]==o2[1]?o1[0]-o2[0]: o1[1]-o2[1]);
        //for(int[] a : arr) System.out.println(a[0]+" "+a[1]);
        System.out.println(Solution(n,arr));

    }
    private static boolean Solution(int n, int[][] arr){
        int start=0;
        int end=0;
        int cnt=0;
        for(int i=0;i<n;i++){
            if(arr[i][0]>=end){
                cnt++;
                end=arr[i][1];
            }
        }
        return cnt==n?true:false;
    }
}

---

public class Solution {

    public boolean canAttendMeetings(List<Interval> intervals) {
        int end=0;
        int cnt=0;
        Collections.sort(intervals, (o1,o2)-> o2.end==o1.end? o1.start-o2.start:o1.end-o2.end);
        for(Interval i : intervals){
            if(end<=i.start){
                end=i.end;
            }else{
                return false;
            }
        }
        return true;
    }
}