This stage is even harder than the previous stage, due to the different donors and recipients present, and there is only one solution. Can you find it?
© 2020 William Pettersson. See the source at Gitlab.
Developed as part of the IP-Match project, funded by Engineering and Physical Sciences Research Council grants EP/P028306/1 and EP/P029825/1.
Congratulations, you assigned all pairs. You can either attempt the next level, which is much harder, or read about how kidney exchange programmes solve these problems in the real world.