rangeSumQuery.cpp

#include<iostream>
#include<bits/stdc++.h>
using namespace std;
int main()
{
    long long int n,q;
    cin>>n>>q;
    long long int arr1[n];
    long long int arr2[n];
    for(int i=0;i<n;i++)
    {
        cin>>arr1[i];
        if(i==0)
        {
            arr2[i]=arr1[i];
        }
        else{
            arr2[i]=arr1[i]+arr2[i-1];
        }
    }
    while(q--)
    {
        long long int l,r;
        cin>>l>>r;
        l--;
        r--;
        long long sum=arr2[r]-arr2[l]+arr1[l];
        cout<<sum<<endl;
    }
    return 0;
}