Psycho killer
A building has 16 rooms, arranged in a 4×4 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.
In the initial configuration, there is one person in each room. The person in the southwest corner is a psycho killer. The psycho 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 site of blood, so he will not enter any room where there is a dead person.
As it happened, from that initial configuration, the psycho killer managed to get out of the building after killing all the other 15 people. What path did he take?
The killer starts by entering the room to the north of his room and killing the person there. Then he comes back to the starting room (This is the only room to which he can come back, because there can’t be any dead body there as it was originally occupied by himself.) Then he proceeds to other rooms in the sequence 2, 3, 4, 8, 7, 6, 10, 9, 13, 14, 15, 11, 12 and 16, exiting from there. (See the figure for room numbers and path taken.)
————————
Added later: He can take an alternate path with first move eastwards (to Room No. 2) and coming back and taking a path mirroring the first solution, along 1 -> 2 -> 1 -> 5 -> 9 -> 13 -> 14 -> 10 -> 6 -> 7 -> 3 -> 4 -> 8 -> 12 -> 11 -> 15 -> 16.
See image for room numbers and the ‘psycho-paths’.
There are more possible paths. The ‘Key’, however, is the return to the starting room after first kill.
Your Answer
More puzzles to try-
What to open puzzle
It\’s 5:00 AM in the morning. You are sleeping. The doorbell rings. It\’s your family, they want to have breakfast. ...Read More »Water of life
It is the water of life, but seeing too much of it is never good. It is what binds families ...Read More »Do you know what word is that?
There is an English word that can be used up to four times in a row without modifying the spelling ...Read More »Strange Visions
It weaken all Person for hours each day. It shows you strange visions while you are away. It takes you ...Read More »Death in a Field
A man is lying dead in a field. Next to him there is an unopened package. There is no other ...Read More »Burning house rescue within time riddle
Group of friends are trapped in a burning house. The house is going to collapse in 12 minutes so they ...Read More »BOXES WITH MARBLES
You have three boxes full of marbles. There are stickers saying “white” “red” “red and white” on them indicating what ...Read More »Walk on the living and Walk on the dead riddle
Walk on the living, they don’t even mumble. Walk on the dead, they mutter and grumble. What are they?Read More »Dark with White
Dark with white markings, And smooth like a rock. Where learning occurs, It helps convey thought. What is it?Read More »Distance travelled by Tyres
John always keeps a spare tyre in his car. To make full use of all the five tyres, he changes ...Read More »More Money Riddle
John had 100k, Jacob has 10k and Johar will have 200k. Who has the most amount of money?Read More »Have Bank but No Money
I have a mouth but I don\’t eat. I have a bank but have no money. I have a bed ...Read More »Who did?
Wednesday, Tom and Joe went to a restaurant and ate dinner. When they were done they paid for the food ...Read More »Algebra Cipher Puzzle
If “P” means “-“, “Q” means “/”, “R” means “+”, and “S” means “*” then find the value of the ...Read More »Secret Message for you Puzzle
Detective Akash is on a secret mission and he wants to send a message to you. Detective Akash got a ...Read More »John and Jill Love Riddle
John and Jill are madly in love with each other. To remind Jill of his pure love, John wants to ...Read More »Man and his boss have the same parents riddle
A man and his boss have the same parents, but are not siblings. How is this possible?Read More »Society Election Votes
At a Society election for president, precisely 963 votes were cast. There is a total of 4 candidates that participate ...Read More »How many seconds in a year
How many seconds are there in a year? Hint: You don’t need a calculator the seconds in ...Read More »Mark the Start Puzzle
Bobby and Wilbur decided to take their respective car out of the garage and race. None of them cheated and ...Read More »