题解

#include<bits/stdc++.h>
using namespace std;
int n, a[100005], x, num, l,r;
int main()
{
    cin >> n >> x;
    for(int i = 1; i <= n; i++)
    {
        cin >> num;
        a[i] = a[i-1] + num;
    }
    for(int i = 1; i <= x; i++)
    {
        cin >> l >> r;
        cout << a[r] - a[l-1] << endl;
    }
}