ZOJ Problem Set - 3922
The first line is an integer T(1 ≤ T ≤ 1000), the number of cases.
There are 3 integers n, e, h in one line for each test case. (1 ≤ n, e, h ≤ 100)
For each case, if it there can be a valid convex regular polyhedron corresponding to n, output the volume in a single line, otherwise, output 0. An answer with absolute error no larger than 1e-5 will be accepted. There're T lines in total.
2 1 1 1 6 1 1
Author: YANG, Xinyu
Source: ZOJ Monthly, February 2016