CSPLib prob049:
"This problem consists in finding a partition of numbers 1..N into two sets A and B such that:
- A and B have the same cardinality
- sum of numbers in A = sum of numbers in B
- sum of squares of numbers in A = sum of squares of numbers in B
More constraints can thus be added, e.g also impose the equality on the sum of cubes. There is no solution for N < 8."
@author Charles Prud'homme
@since 31/03/11