zoj 3622 Magic Number （构造？）

题意是说，能构造多少本元勾股数和勾股数，要求构造的数<=n 所谓本元勾股数，就是三个勾股数没有公因数，两两互质。 由本元勾股数扩大k倍，就可以得到其他勾股数。 而构造本元勾股数的方法如下：

A. Exam time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output An exam for n students will take place in a long and narrow room, so the students will sit in a line in some order. The teacher suspects that students with adjacent numbers (i and i + 1) always studied side by side and became friends and if they take an exam sitting next to each other, they will help each other for sure.

C - C **Time Limit:**1000MS **Memory Limit:**262144KB 64bit IO Format:%I64d & %I64u Submit Status Description Permutation_p_ is an ordered set of integers _p_1, p_2, …, p__n, consisting of n distinct positive integers not larger than n. We’ll denote as_n the length of permutation _p_1, _p_2, …, p__n. Your task is to find such permutation p of length n, that the group of numbers |_p_1 - _p_2|, |_p_2 - _p_3|, …, |p__n - 1 - p__n| has exactly k distinct elements. Input The single line of the input contains two space-separated positive integers n, k (1 ≤ k < n ≤ 105).