for nt in range(int(input())):
n, x, t = map(int,input().split())
c = min(n-1, t//x)
print ((c)*(n-c-1) + (c*(c+1))//2)#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef pair<ll, ll> pl;
#define N 100010
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int t; cin >> t;
while(t--) {
ll n, x, t; cin >> n >> x >> t;
ll d = t / x;
if(d > n - 1) {
cout << ((n - 1) * n) / 2 << "\n";
} else {
ll nn = max(0LL, n - d);
cout << (nn * d + ((d - 1) * d) / 2) << "\n";
}
}
}1671C - Dolce Vita | 1669G - Fall Down |
4D - Mysterious Present | 1316B - String Modification |
1204A - BowWow and the Timetable | 508B - Anton and currency you all know |
1672A - Log Chopping | 300A - Array |
48D - Permutations | 677C - Vanya and Label |
1583B - Omkar and Heavenly Tree | 1703C - Cypher |
1511C - Yet Another Card Deck | 1698A - XOR Mixup |
1702E - Split Into Two Sets | 1703B - ICPC Balloons |
1702F - Equate Multisets | 1700A - Optimal Path |
665C - Simple Strings | 1708A - Difference Operations |
1703E - Mirror Grid | 1042A - Benches |
1676B - Equal Candies | 1705B - Mark the Dust Sweeper |
1711A - Perfect Permutation | 1701B - Permutation |
1692A - Marathon | 1066A - Vova and Train |
169B - Replacing Digits | 171D - Broken checker |