백준 11659

#include <iostream>
#include <vector>
using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    int n, m;
    cin >> n >> m;
    vector<long> dp(n + 1);
    dp[0] = 0;
    for (int i = 1; i <= n; i++) {
        long num;
        cin >> num;
        dp[i] = dp[i - 1] + num;
    }
    for (int i = 0; i < m; i++) {
        int s, e;
        cin >> s >> e;
        cout << dp[e] - dp[s - 1]<<'\n';
    }


    return 0;
}