Codeforces Round #727 (Div. 2)

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 long long n,x,t,m,k;
 4 int main(){
 5     cin>>k;
 6     while(k--){
 7         cin>>n>>x>>t;
 8         m=min(t/x,n);
 9         cout<<m*((n-m-1)+n)/2<<endl;
10     }
11     return 0;
12 }

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 int n,q,l,r,i;
 4 string s;
 5 int main(){    
 6     cin>>n>>q>>s;
 7     vector<int>sum(n+1,0);
 8     for(auto&c:s)sum[i+1]=sum[i]+c-'a'+1,i++;
 9     while(q--){
10         cin>>l>>r;
11         cout<<sum[r]-sum[l-1]<<endl;
12     }
13     return 0;
14 }

~~Jason_liu O(∩_∩)O