first try on eliminating index array
fixes. It looks like it is working
testing code, custom graph. Revert
bug fixes -- changed to using regular vector for parent

* forgot to clear the avail vector
* more forgotten vertex() calls gone
Revert "safety procedures. revert if ok"

This reverts commit cba08296dce90e7f356b23e754a882c963c4af65.
main algorithm now works fine. for small graphs
Revert "testing code, custom graph. Revert"

This reverts commit 256991c5be8a29b512f70ed19e638fe2df28742a.