C++ :

#include<bits/stdc++.h>
using namespace std;
unsigned long long n,q,a[1000005],x,y,b[1000005],ans;
int main(){
    cin>>n>>q;
    for(long long i=1;i<=n;i++) cin>>a[i],b[i]=a[i]+b[i-1];
    while(q--) ans=0,cin>>x>>y,x--,ans=((y/n)*b[n]+b[y%n])-((x/n)*b[n]+b[x%n]),cout<<ans<<endl;
    return 0;
}