[BOJ] 17390 이건 꼭 풀어야 해! (JAVA)

https://www.acmicpc.net/problem/17390

17390번: 이건 꼭 풀어야 해!

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.PriorityQueue;
import java.util.StringTokenizer;

public class Main {
	
    public static void main(String[] args) throws Exception {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuilder sb = new StringBuilder();
        StringTokenizer st = new StringTokenizer(br.readLine(), " ");
        int N = Integer.parseInt(st.nextToken());
        int Q = Integer.parseInt(st.nextToken());
        PriorityQueue<Long> pq = new PriorityQueue<>();
        long[] sum = new long[N + 1];
        st = new StringTokenizer(br.readLine(), " ");
        for (int i = 0; i < N; i++) {
            pq.offer(Long.parseLong(st.nextToken()));
        }

        for (int i = 1; i <= N; i++) {
            sum[i] = sum[i - 1] + pq.poll();
        }

        for (int i = 0; i < Q; i++) {
            st = new StringTokenizer(br.readLine(), " ");
            int start = Integer.parseInt(st.nextToken());
            int end = Integer.parseInt(st.nextToken());
            sb.append(sum[end] - sum[start - 1]).append("\n");
        }

        System.out.print(sb);

    }
	
}