alt Hacker NewsA few additional constraints:
- the boxes are stacked
- the heavy boxes are at the bottom of a stack, and you can't stack a heavy box on top of a light one
- boxes aren't the same size
- some boxes are open, so must be put on top
- storage space and height are limited
Some boxes contain a wolf, some a sheep, and some a cabbage; the sheep and the wolf cannot be left together, nor the cabbage and the sheep.