[백준 / java] 1026 : 보물

https://www.acmicpc.net/problem/1026

package boj1026;

import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[]args)throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        int N = Integer.parseInt(br.readLine());

        int[] A = new int[N];
        Integer [] B = new Integer[N];

        StringTokenizer st = new StringTokenizer(br.readLine());
        for(int i = 0; i < N; i++){
            A[i] = Integer.parseInt(st.nextToken());
        }
        st = new StringTokenizer(br.readLine());
        for(int i = 0; i < N; i++){
            B[i] = Integer.parseInt(st.nextToken());
        }

        Arrays.sort(A);
        Arrays.sort(B,Collections.reverseOrder());

        int sum = 0;
        for(int i = 0; i < N; i++){
            sum += A[i] * B[i];
        }

        System.out.println(sum);


    }
}

Arrays.sort : 오름차순

Arrays.sort(배열명, Collections.reverseOrder()) : 내림차순 → 그대신 안에 있는 객체가 wrapper class여야함