►
Description
Each year, thousands of developers are practicing their coding skills in the *Advent of Code* event. Each day in December, you get a coding puzzle in which you have to help Santa Claus in order to save Christmas. Advent of Code is a great opportunity for those of you who are looking for ways to practice Rust in a fun and entertaining way. Rainer will introduce you to Advent of Code and use some exemplary puzzles to illustrate what you can learn in terms of Rust development.
Slides: https://slides.com/rainerstropek/rust-linz-aoc-2021/fullscreen
Rust Advent of Code Mob Meetup: https://www.meetup.com/Mob-Programming-on-Open-Source-Software/events/282176679
Rainer on Twitter: https://twitter.com/rstropek
Rust Linz on Twitter: https://twitter.com/rustlinz
Speak at Rust Linz: https://sessionize.com/rust-linz
A
A
I
came
across
edward
of
cold
a
little
bit
more
than
a
year
ago,
and
last
year
we
did
advent
of
cold
with
our
kids
and
the
young
coders
at
the
coda
dojo
lynch,
and
we
we
tried
it
and
we
said
hey,
you
know
what
let's
meet
and
let's
do
these
advent
of
code
code
puddles
puzzles.
So
what
is
adword
of
code
admin
of
code?
Is
a
nice
little
a
puzzle
series
that's
happening
between
the
1st
of
december
and
december,
the
25th.
This
is
why
it's
called
advent
of
code.
A
Of
course
the
coding
puzzles
are
really
neatly
embedded
into
stories
where
you
have
to
help
santa
claus
in
order
to
to
save
christmas.
The
puzzles
start
relatively
simple,
but
they
become
harder
and
harder
as
the
days
go
by
in
december.
Luckily,
last
year
at
least
the
the
the
puzzles
was
not
the
hardest
ones.
On
december
23rd,
24th
and
25th,
because
that
would
be
a
little
bit
of
a
coordination
problem,
but
still
in
the
middle
of
december
they
were
pretty
pretty
tricky
sometimes
and
we
enjoyed
it
so
much.
A
The
puzzles
are
focused
on
algorithmic
challenges
and
challenges
about
data
structures,
and
things
like
that.
So
if
you,
if
this
is
something
that
you
are
into
that's
definitely
interesting
for
you
now,
admin
of
code
is
also
a
speeding
contest.
A
speed
coding
contest.
Every
puzzle
is
published
at
midnight
at
eastern
standard
time.
That
is
utc
minus
five.
A
I
think
that's
six
a.m
in
the
morning
here
in
europe,
and
if
you
want
to
get
on
the
leaderboard
on
the
global
leaderboard,
you
have
to
get
up
early
and
you
have
to
be
very
fast
in
order
to
see
your
name
in
in
the
leaderboard.
I
was
blown
away
when
I
saw
how
fast
some
people
code
and
if
speed
coding,
is
something
that
you
are
passionate
about,
definitely
try
it.
A
The
good
news
is,
although
if
you
are
not
one
of
the
fastest
coders
in
the
world,
just
to
give
you
an
impression,
advent
of
code
is
done
by
more
than
150
000
developers
each
year,
I
think.
Last
year
there
were
160
000
of
the
first
day.
Something
like
this.
So
if
you
are
not
one
of
the
fastest
ones
in
this
area,
but
you
are
in
a
community
like
our
coding
club
or
female
coders
or
your
school
or
your
your
community.
A
You
can
set
up
private
leader
boards
and
gather
stars
there,
and
then
you
have
a
private
challenge
a
little
bit
and
yeah.
You
are
also
learning
things.
I
think
that
it's
a
great
practice
a
great
possibility
to
practice
a
new
programming
language
like
rust,
because
admin
of
code
is
completely
language
agnostic.
You
can
start
with
rust,
continue
with
go,
go
on
with
c
sharp
move
to
python
and
even
do
some
things
with.
I
don't
know
wolfram
alpha
or
scratch
or
excel
it
doesn't
matter
and
of
course,
address
of
code
is
a
lot
of
fun.
A
So
let
me
quickly
describe
you
in
just
a
few
minutes
how
advent
of
code
works?
This
is
your
goal
this
this
picture
here
is
your
goal,
because
this
is
how
your
advent
of
code
event
page
should
look
like
at
the
end
of
the
of
the
year.
Of
course,
I
hope
at
least
we'll
get
a
new
ascii
art
for
this
year,
but
this
is
the
my
page.
A
A
Now
all
the
puzzles
are
embedded
in
a
kind
of
story
about
santa
claus.
I
also
mention
I
already
mentioned
that,
but
from
a
technical
perspective,
it's
super
interesting
that
all
the
puzzles
come
with
some
examples,
and
in
this
case
I
took
a
very
simple
entry-level
puzzle
from
I
think
it's
2019,
where
you
just
have
to
take
a
bunch
of
numbers.
You
have
to
divide
them
by
three
round
it
down
and
subtract
two
to
get
the
result,
and
here
you
see
in
the
in
the
yellow
rectangle.
A
You
see
the
examples
that
I
meant
with
the
solutions.
So
what
you
can
do
on
each
day.
You
can
take
these
examples
and
do
test
driven
development,
so
you
can
write
the
unit
tests
first
and
then
write
the
algorithm.
So
let
me
quickly
show
you
how
that
could
look
like
in
an
example
that
I
have
done
here.
You
see
oops.
Sorry.
I
forgot
to
start
my
zoom
zooming
tool.
Now
it
should
work
here.
You
see
this
beautiful
function.
A
This
is
the
difficult
function
that
I
had
to
write
and
then
you
can
use,
for
instance,
unit
testing.
This
is
how
I
typically
do
it.
I
create
a
test
module
here
in
rust
and
then
I
add
the
the
samples
here
in
my
unit
test,
so
you
can
really
do
test
driven
development
that
works
pretty
well
and
is
also
nice
for
people
who
start
coding
now
then
it's
getting
it's
getting
real
because
you
get
your
personal
puzzle.
A
Input
admin
of
code
does
not
have
a
single
input,
a
real
world
input
for
everybody,
but
you
get
your
personal
input.
You
download
it
and
it
looks
something
like,
for
instance,
this
one
here.
The
puzzle.
Input
is
always
kind
of
a
text
input.
So
here
you
can
practice
things
like
file
handling.
You
have
to
read
the
file.
You
can
practice
things
like
regular
expressions,
for
instance
working
with
matches
or
capture
groups.
A
If
you
don't
know
what
capture
groups
is,
adword
of
code
is
a
great
way
to
find
out
splitting
strings
into
spans,
doing
some
alloc
free
algorithms
with
rust.
That's
a
lot
of
fun,
the
the
advent
of
code.
Guys
say
you
shouldn't
download
the
input
via
http
requests
and
do
that
pretty
frequently,
because
that's
because
that
might
put
a
stress
on
the
server,
so
you
are
encouraged
to
download
the
file
by
copying
and
pasting
it
putting
it
into
a
local
file
and
then
do
all
the
development
locally.
A
If
you
really
download
the
the
demo
data
via
http
automatically,
please
do
some
caching
in
any
way
to
not
overstress
the
servers.
Now,
then,
you
have
to
go
on
and
process
this
input
properly
and
nearly
every
time
it
is
about
a
kind
of
iterator
or
generator.
So
this
is
a
great
thing.
If
you
are
new
to
rust,
you
can
practice
iterators
building
custom
iterators,
for
instance.
Recently
I
took
a
look
at
one
of
the
the
the
examples
last
year
and
I
wanted
to
find
out
what
about
this
yield
macro.
A
If
you
have
never
seen
it,
google
it.
I
was
looking
for
a
kind
of
yield
operator
in
rust.
There
is
no
yield
operator
in
your
rust,
yet
you
probably
know
that,
but
there
are
crates
about
it
and
I
used
an
adword
of
code
puzzle
to
dive
into
that
matter,
because
I
simply
wanted
to
play
with
it,
and
admin
of
code
is
a
great
place
to
learn
about
iterators
and
generators
and
then
at
the
end
you
come
up
with
an
answer.
A
It's
typically
a
number
or
a
text
you
type
it
in,
and
hopefully
you
get
will
get
your
first
star,
but
that's
not
all
you're
not
done
yet,
because
then
the
second
puzzle
appears
every
day
consists
of
two
puzzles.
You
have
to
earn
a
second
star,
so
you
get
a
slightly
more
difficult
version
of
the
original
puzzle,
and
that
is
a
great
possibility
to
go
back
to
change
your
unit
tests
or
add
new
unit
tests.
You
go
back
into
coding
and
especially
important.
A
You
practice
refactoring,
you
have
an
existing
algorithm
and
now
you
have
to
change
it
to
generalize
it
to
introduce
abstractions.
So
you
can
use
common
code
for
both
problems
and
make
the
different
things
really
different.
So
I
personally
think
this
is
a
great
way
of
learning
and
practicing
refactoring
in
a
language
that
you
know
or
that
you're
currently
learning
and
that
will
lead
you
to
hopefully
two
stars,
and
that
is
the
goal
of
every
day
and
at
the
end
on
december
the
25th
you
hopefully
have
50
stars.
A
Let
me
tell
you
a
few
tips
that
I
have
learned
some
of
them
the
hard
way
last
year,
for
instance,
think
about
what
you
want
to
get
out
of
edward
of
code.
Maybe
you
are
into
speed
coding.
If
you
are
into
speed
coding,
don't
forget
your
alarm
clock.
You
have
to
get
up
early
and
quick
and
dirty
coding
is
perfectly
fine.
Maybe
maybe,
if
you
really
want
to
go
into
speed
coding,
you
shouldn't
take
a
new
language.
A
You
should
take
a
language
that
you
really
know
really
very
no
very
good
and
you
try
to
get
up
get
the
the
correct
result
as
fast
as
possible,
but
you
can
also
have
a
different
mindset.
You
can
say
I
want
to
practice
a
new
language
and
then
maybe
you
focus
more
on
quality
and
idiomatic
coding,
but
don't
underestimate
the
additional
effort,
if
you
try
to
do
it
with
a
different
language
that
you
don't
already
know,
because
at
a
certain
point
in
in
december,
the
challenges
will
be
rather
tricky.
A
Yeah
and
of
course
maybe
you-
you
use
the
old
versions
to
come
up
with
a
kind
of
project
or
workspace
structure.
Think
about
how
you
want
to
structure
your
work
with
the
unit
tests
and
so
on.
So
you
do
not
need
to
build
it
on
december,
the
first
or
you
use
the
first
puzzles,
which
are
pretty
simple
on
the
first
few
days
to
get
into
edit
of
code.
A
Speaking
of
oh
yeah,
the
last
one.
Sorry,
if
you
really
want
to
have
50
stars
on
the
december
25th,
hey
prepare
your
family
early,
that
you
are
going
to
spend
some
time
in
front
of
the
computer
on
december,
the
24th
and
the
25th,
because
maybe
it's
good
to
give
them
a
heads
up.
If
you
are
planning
to
do
that,
one,
okay,
speaking
about
communities!
What
are
we
going
to
do
with
advent
of
code
and
communities
in
lynx?
A
We
are
going
to
do
again
advent
of
code
with
the
kids
and
the
young
coders
at
adword
of
code
at
the
code
of
dojolins.
We
will
meet
daily
and
solve
the
puzzles
together
and
last
year,
by
the
way
two
young
coders
who
are
just
in
school,
one
of
them
were
was
was
13
year
old,
managed
to
get
50
stars
on
december
25th.
So
they
really
made
the
challenge.
That
was
great.
A
A
Awesome
fred
contacted
me
and
he
asked
me
whether
he
can
share
a
meetup
that
they
will
do
in
vienna
in
relation
to
advent
of
code,
and
I
immediately
invited
fred
to
come
to
us
today
at
the
end
of
this
lightning
talk,
and
maybe
you
can
tell
us
a
little
bit
what
you
are
going
to
do
in
terms
of
advent
of
code
and
rust
in
december.
2021.
B
B
This
is
called
being
a
member
of
the
mob
or
a
mother,
so
each
person
spends
a
few
minutes
in
the
in
the
role
and
this
sequence
rotates
through
the
group
until
the
task
is
done
so
nowadays,
due
to
isolation
and
covalent
and
so
on.
Mob
programming
is
primarily
done
by
a
zoom
screen
sharing
and
online
ides.
B
So
I
want
to
talk
a
bit
about
the
mob
programming
on
open
source
software
meetup
group.
So
this
is
a
meetup
group
with
about
200
plus
members
now,
and
the
main
focus
of
the
group
is
to
bring
people
together
to
do
mob
programming
on
open
source
software,
like
maybe
fixing
a
bug
or
adding
a
new
feature.
Each
session
is
about
three
hours
long
and
usually
concludes
with
a
pull
request
to
the
open
source
project.
B
These
happen
quite
often,
usually
on
a
week
once
a
week
or
so
on,
wednesdays,
and
then
what
about
the
advent
of
the
rustic
mob
event,
so
that
event
is
also
a
meet
up
event
as
part
of
the
ma
programming
and
open
source
software
meetup
group.
So
this
event
is
is
organized
by
harald
kushigan.
I,
and
it
is
about
working
on
the
advent
of
code
problems
using
rust
and
in
a
mob
programming
setting.
B
We
think
that
it
will
be
a
really
good
way
to
learn
about
mob
programming
and,
if
you
want
to
learn
rust,
then
to
learn
rust
and
to
also
improve
problem
solving
skills.
That
being
said,
you
don't
have
to
be
new
to
any
of
these
three
things
to
join,
but
also,
if
you
are
new
and
if
you
are
a
beginning,
you're
very
welcome
to
join.
So
our
first
event
will
be
this
coming
wednesday,
the
1st
of
december.
B
A
A
Now
you
have
an
opportunity
to
work
on
it
for
kids
and
with
kids
in
the
coda
dojo,
and
if
you
are
a
professional
developer
and
you
want
to
get
in
touch
with
other
professional
developers,
learning
rust
or
who
are
passionate
about
rust
than
the
mark,
then
the
meetup
that
fred
just
told
us
about
is
a
great
play,
a
great
way
to
do
that
for
all
who
are
interested,
but
you
don't
find
it
on
the
internet.
I
will
post
my
slide.
A
That's
slides
that
I
have
shown
you
now
here
in
the
in
the
youtube
chat
in
a
second
and
there
we
have
a
link
to
the
meetup
of
fred.
So
you
you
do
not
need
to
start
googling
immediately.
You
will
find
the
link
in
the
in
the
youtube
chat
and,
of
course,
I
will
also
paste
the
link
in
the
discord
server.
Fred.
Thank
you
very
much
for
visiting
us,
and
we
wish
you
a
nice
december
and
a
lot
of
fun
with
the
advent
of
code
puzzles.