CF1539A Contest Start

### 题意描述 有 $n$ 个人参加某个竞赛，他们以 $x$ 分钟的间隔开始。 每个参赛者的比赛时长为 $t$ 分钟，因此第一个参赛者在 $t$ 时间结束比赛，第二个参赛者在 $t+x$ 时间结束比赛，依此类推。当一个参赛者完成比赛时，他们的不满意程度等于已开始比赛（或现在正好开始）但还没有完成比赛的参赛者人数。 求所有参赛者的不满意程度之和。

第一行包含一个整数 $k$ ( $1\leq k\leq 1000$)，表示数据组数。 接下来的每一行包含三个整数 $ n,x,t$ ( $1\leq n,x,t\leq 2⋅10^9$)，分别为参与者的数量，开始时间间隔和比赛时长。

一共 $k$ 行，在第 $i$ 行中输出第 $i$ 组数据中参与者的不满意程度之和。

In the first example the first participant starts at $ 0 $ and finishes at time $ 5 $ . By that time the second and the third participants start, so the dissatisfaction of the first participant is $ 2 $ . The second participant starts at time $ 2 $ and finishes at time $ 7 $ . By that time the third the fourth participants start, so the dissatisfaction of the second participant is $ 2 $ . The third participant starts at $ 4 $ and finishes at $ 9 $ . By that time the fourth participant starts, so the dissatisfaction of the third participant is $ 1 $ . The fourth participant starts at $ 6 $ and finishes at $ 11 $ . By time $ 11 $ everyone finishes the contest, so the dissatisfaction of the fourth participant is $ 0 $ . In the second example the first participant starts at $ 0 $ and finishes at time $ 2 $ . By that time the second participants starts, and the third starts at exactly time $ 2 $ . So the dissatisfaction of the first participant is $ 2 $ . The second participant starts at time $ 1 $ and finishes at time $ 3 $ . At that time the third participant is solving the contest.