Codeforces Round #727 (Div. 2)

#include <bits/stdc++.h>
using namespace std;
long long n,x,t,m,k;
int main(){
    cin>>k;
    while(k--){
        cin>>n>>x>>t;
        m=min(t/x,n);
        cout<<m*((n-m-1)+n)/2<<endl;
    }
    return 0;
}

#include <bits/stdc++.h>
using namespace std;
int n,q,l,r,i;
string s;
int main(){    
    cin>>n>>q>>s;
    vector<int>sum(n+1,0);
    for(auto&c:s)sum[i+1]=sum[i]+c-'a'+1,i++;
    while(q--){
        cin>>l>>r;
        cout<<sum[r]-sum[l-1]<<endl;
    }
    return 0;
}