A building has 16 rooms, arranged in a 4x4 grid. There is a door between every pair of adjacent rooms ("adjacent" meaning north, south, west, and east, but no diagonals). Only the room in the northeast corner has a door that leads out of the building.
At the start, there is one person in each room. The person in the southwest corner is a serial killer. The killer has the following traits: If he enters a room where there is another person, he immediately kills that person. But he also cannot stand the sight of blood, so he will not enter any room where there is a dead person.
Only he knows about the exit door in the northeast corner of the building.
Part 1: As it happened, from that initial configuration, the killer managed to get out of the building after killing all the other 15 people. What path did he take?
(Details for part 1: The other 15 people do not change rooms)
Part 2: If everyone in the bulding knows about the exit door and that there is a serial killer in the SW corner room, what is the maximum and the minimum number of people that the killer can kill assuming that if any one of the other 15 people is in the NE corner room, he will go out of the building (same day)?
(Details for part 2: At a time, there can only be one person (excluding the killer) in one room. If a person A wanting to change room sees someone else already in the room, A will look to move to some other room (or go back to his room). If two people walk into an empty room simultaneously, only one of them stays in that room and the other one looks for some other room (or goes back to his room). The other 15 people can change the room once a day and the killer changes the room once a day.)
Question
Guest
A building has 16 rooms, arranged in a 4x4 grid. There is a door between every pair of adjacent rooms ("adjacent" meaning north, south, west, and east, but no diagonals). Only the room in the northeast corner has a door that leads out of the building.
At the start, there is one person in each room. The person in the southwest corner is a serial killer. The killer has the following traits: If he enters a room where there is another person, he immediately kills that person. But he also cannot stand the sight of blood, so he will not enter any room where there is a dead person.
Only he knows about the exit door in the northeast corner of the building.
Part 1: As it happened, from that initial configuration, the killer managed to get out of the building after killing all the other 15 people. What path did he take?
(Details for part 1: The other 15 people do not change rooms)
Part 2: If everyone in the bulding knows about the exit door and that there is a serial killer in the SW corner room, what is the maximum and the minimum number of people that the killer can kill assuming that if any one of the other 15 people is in the NE corner room, he will go out of the building (same day)?
(Details for part 2: At a time, there can only be one person (excluding the killer) in one room. If a person A wanting to change room sees someone else already in the room, A will look to move to some other room (or go back to his room). If two people walk into an empty room simultaneously, only one of them stays in that room and the other one looks for some other room (or goes back to his room). The other 15 people can change the room once a day and the killer changes the room once a day.)
Link to comment
Share on other sites
13 answers to this question
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.