Due to backing implementation of chaining rule, the first found chain may not be the minimal length of all possible found chains - the first found chain should hold the minimal index of conclusion candidate.
If it is required that the length should be considered, we should sort for all possible found chains, and return one having the minimal length.
Here we should append an extra rule for optimization: if we have already found a chain whose length is less than or equals to 6, it is already a shortest chain because we cannot find a chain with just one strong link (it can be replaced with some other techniques, called "type 2") and two strong links (replaced with X-Wing, skyscraper, two-string-kite and turbot fish).
For further consideration, if we search for grouped cases, we should relax the value to 4 in order making missing ALS-XZ's can be found here.
In addition, here we only consider for elimination cases of chaining - there's no two-strong-link chains with assignment conclusions exist.
Such optimization can make a quick return to avoid exaustive searching. However, this is an unsafe optmization, but we can guarantee that all chains with just one link cannot exist here.
Due to backing implementation of chaining rule, the first found chain may not be the minimal length of all possible found chains - the first found chain should hold the minimal index of conclusion candidate.
If it is required that the length should be considered, we should sort for all possible found chains, and return one having the minimal length.
Here we should append an extra rule for optimization: if we have already found a chain whose length is less than or equals to 6, it is already a shortest chain because we cannot find a chain with just one strong link (it can be replaced with some other techniques, called "type 2") and two strong links (replaced with X-Wing, skyscraper, two-string-kite and turbot fish).
For further consideration, if we search for grouped cases, we should relax the value to 4 in order making missing ALS-XZ's can be found here.
In addition, here we only consider for elimination cases of chaining - there's no two-strong-link chains with assignment conclusions exist.
Such optimization can make a quick return to avoid exaustive searching. However, this is an unsafe optmization, but we can guarantee that all chains with just one link cannot exist here.