Java 代码

import java.util.*;
public class Main{
    static int[] tmp;
    static long res = 0;
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int[] nums = new int[n];
        for(int i = 0; i < n; i++){
            nums[i] = sc.nextInt();
        }

        int[] presum = new int[n+1];
        presum[0] = 0;
        for(int i = 1; i <= n; i++){
            presum[i] = presum[i-1]+nums[i-1];
        }
        for(int i = 0; i < m; i++){
            int l = sc.nextInt();
            int r = sc.nextInt();
            System.out.println(presum[r]-presum[l-1]);
        }
    }

}