The origin of this puzzle is not known.
Puzzle and Goal
An unsolved puzzle consists of a NxN square of numbers. Along the top and left are number clues.
The goal is to locate N 3x1 or 1x3 regions that satisfy the clues.
The solved grid must satisfy the following conditions:
For each integer from 1 to N, there is one region whose numbers sum to that value.
The numbers on the top and left indicate the sum of the cells within regions in that rank.
A cell can be in at most one region.