A14597. Training Session
编程题
普及/提高-
知识点
题目描述
Monocarp is the coach of the Berland State University programming teams. He decided to compose a problemset for a training session for his teams.
Monocarp has $n$ problems that none of his students have seen yet. The $i$ -th problem has a topic $a_i$ (an integer from $1$ to $n$ ) and a difficulty $b_i$ (an integer from $1$ to $n$ ). All problems are different, that is, there are no two tasks that have the same topic and difficulty at the same time.
Monocarp decided to select exactly $3$ problems from $n$ problems for the problemset. The problems should satisfy at least one of two conditions (possibly, both):
- the topics of all three selected problems are different;
- the difficulties of all three selected problems are different.
Your task is to determine the number of ways to select three problems for the problemset.
Monocarp has $n$ problems that none of his students have seen yet. The $i$ -th problem has a topic $a_i$ (an integer from $1$ to $n$ ) and a difficulty $b_i$ (an integer from $1$ to $n$ ). All problems are different, that is, there are no two tasks that have the same topic and difficulty at the same time.
Monocarp decided to select exactly $3$ problems from $n$ problems for the problemset. The problems should satisfy at least one of two conditions (possibly, both):
- the topics of all three selected problems are different;
- the difficulties of all three selected problems are different.
Your task is to determine the number of ways to select three problems for the problemset.
输入格式
The first line contains a single integer $t$ ( $1 \le t \le 50000$ ) — the number of testcases.
The first line of each testcase contains an integer $n$ ( $3 \le n \le 2 \cdot 10^5$ ) — the number of problems that Monocarp have.
In the $i$ -th of the following $n$ lines, there are two integers $a_i$ and $b_i$ ( $1 \le a_i, b_i \le n$ ) — the topic and the difficulty of the $i$ -th problem.
It is guaranteed that there are no two problems that have the same topic and difficulty at the same time.
The sum of $n$ over all testcases doesn't exceed $2 \cdot 10^5$ .
The first line of each testcase contains an integer $n$ ( $3 \le n \le 2 \cdot 10^5$ ) — the number of problems that Monocarp have.
In the $i$ -th of the following $n$ lines, there are two integers $a_i$ and $b_i$ ( $1 \le a_i, b_i \le n$ ) — the topic and the difficulty of the $i$ -th problem.
It is guaranteed that there are no two problems that have the same topic and difficulty at the same time.
The sum of $n$ over all testcases doesn't exceed $2 \cdot 10^5$ .
输出格式
Print the number of ways to select three training problems that meet either of the requirements described in the statement.
输入输出样例
输入 #1
2 4 2 4 3 4 2 1 1 3 5 1 5 2 4 3 3 4 2 5 1
输出 #1
3 10
说明/提示
In the first example, you can take the following sets of three problems:
- problems $1$ , $2$ , $4$ ;
- problems $1$ , $3$ , $4$ ;
- problems $2$ , $3$ , $4$ .
Thus, the number of ways is equal to three.
- problems $1$ , $2$ , $4$ ;
- problems $1$ , $3$ , $4$ ;
- problems $2$ , $3$ , $4$ .
Thus, the number of ways is equal to three.