← 返回题目
题库练习 [COCI-2007_2008-contest3]#3 DEJAVU
← 上一题 下一题 →

A1115 | [COCI-2007_2008-contest3]#3 DEJAVU

来源COCI
时间限制1s
内存限制128MB
通过 / 提交0/0

题目描述

N points are placed in the coordinate plane.
Write a program that calculates how many ways we can choose three points so that they form a right triangle with legs parallel to the coordinate axes.
A right triangle has one 90-degree internal angle. The legs of a right triangle are its two shorter sides.

输入格式

The first line of input contains the integer N (3 ≤ N ≤ 100000), the number of points.
Each of the following N lines contains two integers X and Y (1 ≤ X, Y ≤ 100 000), the coordinates of one point.
No pair of points will share the same pair of coordinates.

输出格式

Output the number of triangles.

输入输出样例

输入 #1
3 
4 2 
2 1 
1 3
输出 #1
0
输入 #2
5 
1 2 
2 1 
2 2 
2 3 
3 2
输出 #2
4
输入 #3
6 
10 10 
20 10 
10 20 
20 20 
30 20 
30 30
输出 #3
8
C++ 编辑器
输入
输出