Three missionaries and three cannibals are on one side of the river, wanting to get across.

Unfortunately, the only boat available can hold a maximum of two people. The missionaries, wanting to stay safe, can never be on a side with more cannibals than missionaries (even for a moment!). The boat cannot travel under its own power, so there must be at least one person on board for it to cross.

How can the missionaries get safely across?

I managed:
(M = Missionary, C = Cannibal)
MMM  CCC  |               |

1) MM CC   |      ->      | M C
2) MMM CC |      <-      | C
3) MMM       |      ->      | CCC
4) MMM C    |     <-      | CC
5) M C        |      ->      | MM CC
6) MM CC    |      <-      | M C
7) CC          |     ->       | MMM C
8) CCC       |      <-      | MMM
9) C            |      ->      | MMM CC
10) M C       |      <-      | MM CC
11)              |      ->      | MMM CCC

Wouldn't  it be better and more efficient if the cannibals just ate the missionaries and then crossed in three boat rides? (no offence intended against anyone at all)

Posted by Steph on 2005-05-31 14:33:48