Editorial for ECOO '12 R2 P4 - Lo Shudoku
Submitting an official solution before solving the problem yourself is a bannable offence.
Exhaustive Search
An exhaustive search of all possible moves would be difficult to write and will not finish in time, so another strategy is needed. Perhaps a breadth first search would work in some cases, but still in the worst case would still have a bad running time and memory requirements. As a ballpark estimate, in the worst case you have to consider
Observations
If you can find a fast enough way to transform a
There is an upper bound of
It actually does not matter to the number of moves required whether you fill in the blanks at the beginning or at the end.
Final Strategy
Try each of the
Comments