Discrete Mathematics for Computer Science

Exercises 369

19. The Hall of Horrors at an amusement park challenges you to enter at the Start door
    and find your way to the Escape door. After passing through a door, the door closes
    and locks. How many doors can you leave closed as you find your way from the Start
    door to the Escape door? The layout of the Hall of Horrors is shown below.

Start

A B C D

G : F E

H I

Q

0 N K

R -, -4 -

P I M L

L I

Escape

20. A real estate agent wants to show the three houses shown. Lay out a tour that goes
    through each door.

2 3 4 5

(^2 3 4 6 7 8 9)
1 10 11 12 13
]E F- F4 - -E-
House with 18 doors House with 31 doors
(a) (b)
(^2 3)
6 5 4
House with 19 doors
(c)