[백준] 11659번

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

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

        int N = Integer.parseInt(st.nextToken());   // 수의 개수
        int M = Integer.parseInt(st.nextToken());   // 합을 구해야 하는 횟수
        long[] arr = new long[N + 1];
        st = new StringTokenizer(br.readLine());

        for (int i = 1; i <= N; i++) {
            arr[i] = arr[i - 1] + Integer.parseInt(st.nextToken());
        }

        for (int i = 0; i < M; i++) {
            st = new StringTokenizer(br.readLine());
            int a = Integer.parseInt(st.nextToken());
            int b = Integer.parseInt(st.nextToken());

            System.out.println(arr[b] - arr[a - 1]);
        }
    }
}