A friend at work came across this article today on the math of matching donors to recipients. In some instances, specifically with kidney transplants, recipients might have a willing donor, but they aren’t a tissue match. With the help of an altruistic donor–someone who wants to donate an organ without a specific recipient in mind–surgeons have performed a chain of transplants, matching donors and recipients from different hospitals in order to get everyone the organ they need. The willing donor that isn’t a match may not donate their organ directly to their friend or loved one, but in the end, their intended recipient gets the organ they need. The problem is, how to figure out the optimal distribution when the chain of recipients is donors gets long. This kind of computation is called an NP-hard problem, or Non-Deterministic Polynomial-time hard. Which to me, the math novice, means it’s a super hard problem.

Read more over at Ars Technica:

The math of organ donation: Kidneys are an NP-hard problem