11 人解决，14 人已尝试。
12 份提交通过，共有 36 份提交。
5.6 EMB 奖励。
单点时限: 2.0 sec
内存限制: 256 MB
There are n points given in a space. There are no three points, such that they lie on the same straight line. Each pair of points is connected by a segment coloured red or black. Each triangle, whose sides have the same colour is called a monochromatic triangle. We are given a list of all red segments and we want to find the number of all monochromatic triangles.
Write a program that:
reads the following data: the number of points, the number of red segments and their list,
finds the number of monochromatic triangles,
writes the result.
In the first line there is one integer n, 3 <= n <= 1000, which equals the number of points.
In the second line there is one integer m, 0 <= m <= 250000, which equals the number of red segments.
In each of the following m lines there are two integers p and k separated by a single space, 1 <= p < k <= n. They are numbers of vertices which are ends of a red segment.
In the first line there should be written one integer - the number of monochromatic triangles.
6 9 1 2 2 3 2 5 1 4 1 6 3 4 4 5 5 6 3 6
2
11 人解决，14 人已尝试。
12 份提交通过，共有 36 份提交。
5.6 EMB 奖励。