For the meetup #51, the Amsterdam Clojure meetup together with Elmar Reizen hosted a Clojure Dojo. The proposed problem was to write a nonogram solver. This is the presentation I used to introduce the problem to the developers.

1. Code Dojo #3

2. Rules of engagement
1/2
-­‐ We
split
in
pairs
-­‐ We
receive
the
problem
to
solve
-­‐ We
use
pair
programming
to
solve
the
problem

3. Rules of engagement
2/2
-­‐ We
use
the
pomodoro
technique
-­‐ After
a
pomodoro,
you
can
switch
pairs
-­‐ After
the
3rd
pomodoro,
every
pair
shows
the
code
on
screen

4. Rules of engagement
2/2
-­‐ The
goal
is
-­‐ To
have
fun
-­‐ To
see
different
approaches
-­‐ To
exercise
our
Clojure
kung
fu
-­‐ The
goal
is
NOT
-­‐ To
be
the
best
-­‐ To
be
an
a$$
with
the
others
in
any
possible
way

5. Ready?!

6. Nonograms solver
1/4
Li’l
Joop
is
struggling
with
nonograms,
help
him
find
a
solution!

7. Nonograms solver
2/4
A
nonogram
is
a
Japanese
puzzle
where
cells
in
a
grid
must
be
colored
or
left
blank
according
to
the
numbers
appearing
at
the
side
of
the
grid:

8. Nonograms solver
3/4
The
numbers
represent
consecutive
colored
blocks:
Spaces
are
not
represented
in
the
constraints:

9. Nonograms solver
4/4
Your
program
can
read
nonogram
puzzles
from
files
with
the
following
syntax
(EDN):
{
:size [10 10]
:rows [[] [1 1] [1] [2 1 1] [1 1 1] [1 2 1 1] [1] [1] [] []]
:cols [[] [1] [] [3] [1 1] [] [5] [1] [1 4] []]
}

10. Nonograms solver
4/4
The
program
then
prints
out
the
solution.
You
will
use
“_”
to
mark
empty
cells
and
“X”
to
mark
colored
cells:
_ _ _ _ _ _ _ _ _ _
_ _ _ _ _ _ X _ X _
_ _ _ _ _ _ X _ _ _
_ _ _ X X _ X _ X _
_ _ _ X _ _ X _ X _
_ X _ X X _ X _ X _
_ _ _ _ _ _ _ _ X _
_ _ _ _ _ _ _ X _ _
_ _ _ _ _ _ _ _ _ _
_ _ _ _ _ _ _ _ _ _

11. GO!

13. Bonus level: colors!
Nonogram
puzzles
now
involve
colors:
{
:size [10 10]
:rows [{:blue 1
:grey 1
:red 1
:red 1
:grey 1
:blue 1} …]
:cols [{:blue 1
:orange 6}]
}