Isn&#x27;t the donor-patient problem a vertex cycle cover? Finding a minimum one is NP-complete, how exactly is this one applied?<p>edit:<p>found a bit more information <a href="https:&#x2F;&#x2F;www.siam.org&#x2F;news&#x2F;news.php?id=1474" rel="nofollow">https:&#x2F;&#x2F;www.siam.org&#x2F;news&#x2F;news.php?id=1474</a>