Task 1: "Cryptic Message:

The communication system of an office is broken and messages received
are not completely reliable. To send the message Hello 6 times, it ended
up sending these following:

H x l 4 !
c e - l o
z e 6 l g
H W l v R
q 9 m # o

Similarly another day we received a message repeatedly like below:

P + 2 l ! a t o
1 e 8 0 R $ 4 u
5 - r ] + a > /
P x w l b 3 k \
2 e 3 5 R 8 y u
< ! r ^ ( ) k 0

Write a script to decrypt the above repeated message (one message repeated
6 times).

HINT: Look for characters repeated in a particular position in all six
messages received.
"

My notes: ah, so pick maxfreq letter in each column?

Task #2: "Is the room open?

There are 500 rooms in a hotel with 500 employees having keys to all the
rooms. The first employee opened main entrance door of all the rooms. The
second employee then closed the doors of room numbers 2,4,6,8,10 and
so on to 500. The third employee then closed the door if it was opened
or opened the door if it was closed of rooms 3,6,9,12,15 and so on to
500. Similarly the fourth employee did the same as the third but only
room numbers 4,8,12,16 and so on to 500. This goes on until all employees
has had a turn.

Write a script to find out all the rooms still open at the end.
"

My notes: sounds pretty easy, two nested for loops, but one of those questions
where I can't predict in advance what the answer will be.

But having written the naive roomopen[r] based solution, I find that the
answer is: the open rooms are all the room numbers that are exact squares!
I'm not sure why, but I then implemented that more directly, with no
arrays.  I then translated that into Postscript too, see the postscript
directory:-)