KL45paaGYsA

so hello there and welcome to a tutorial
my name is tender-back xin this time
we're gonna be going over something
really interesting I know you're all
gonna love it and this app is really fun
to test you because this is cold v he's
in tic-tac-toe and you'll see exactly
why I chose teasing for the word in just
a minute
the reason I chose teasing is because
well let's take tac toe game it's
impossible to beat you can only draw
with it and you can only lose against it
so let's get straight into it I'll
explain all the rules that falls the
basic algorithm it has and then we will
get straight into the code where I will
explain and I'll also give a little demo
and then I'll explain the code if you
can find any way to beat this game make
sure you tell me either in the comments
or mail me mail me my mail is tangent
Manion gmail.com and that will be in the
description if you don't understand that
so please tell me I will include a fix
in for that in my algorithm but let's
get started and as you can see here I
devised seven rules in tic-tac-toe these
are from Wikipedia link to this will be
down in the description below not
exactly sure who wrote this but that
will also be in the description but
these seven rules will help the computer
decide exactly what it needs to do on
this turn of its tic-tac-toe game so as
you can see the first rule is if you can
win win don't do anything else
don't walk your opponent from winning
just wait if you can win because you're
gonna end the game anyway and you would
have won next if your opponents about to
win block him from winning third if your
opponent tries to fork you block his
fork before he can and this doesn't
really apply to my algorithm because
it's really complicated but the rule for
humans is that fork the other player if
you could possibly could and if you
can't do all of these strategies then go
for the center if the center is taken
then go for the corners if the corners
are taken then go for the sides so I'm
gonna be sharing with you first of all
have an example of all the first the
first four rules actually the first
rules that the computer would use and
also just as an addition the fourth rule
that the human would use and then these
five six and seven rules I will explain
with an example game that I actually
played with the computer and I'll
explain all of its logic and reasoning
behind what the moves it did so let's
get started here I'm gonna start off
with rule number one which is if you
can't win just win don't bother doing
anything else so as you can see me here
we have a board and I'm just going to
start let's just say X is over here and
X isn't the most smartest of opponent
see it's a really new take back to a
player he hasn't played many games about
oh he's a really seasoned experienced
player so it isn't really a fair match
so let's just say all goes for the
center like most normal and most really
good take back to hers no that's where
you get the best moves so then let's
just say X goes over here for some
reason
now all we'll try it's best to go here
now what's gonna happen is let's just
say oh again isn't the brightest and he
doesn't realize that oh is threatening a
three X will play over here by mistake
Oh we'll play over here and win so this
is one of the examples if you can win
just win don't do anything else just win
that's it
apart from that we have the second rule
which is if your pony can win make sure
you block him let's just give a little
example this let's just say X plays over
here let's just say maybe old plays over
here or actually no I'm going to say X I
mean o plays over here okay now let's
just say X plays over here okay now X
can win like this so oh it's gonna play
over here now okay one like this so X is
gonna play over here and the rest of
this game would probably end in a draw
unless one of them can think of
something really smart to do or if one
of them makes a really foolish mistake
after that we have if your opponent
tries to fork you block that opponent
from forking so let's actually see how
this works
so the basic fork strategy that I've
learnt is that you choose a corner look
around it
try to fill these and try to fill the
inside then try to essentially kill it
then you actually do have two openings
here and then your opponent can't block
and just in case you were wondering
exactly what fork is let me explain that
to you right now a fork is when you have
two openings in six Actos that you could
possibly win and forking is actually one
of the most challenging tactics first of
all but it's also the best tactic if you
want to win and this to me doesn't work
if you play with one player because they
will eventually find out what you always
do in a game and they're always they're
gonna know how to actually go against
you so that's why this is really good
against new players who really don't
know much tic-tac-toe that they don't
have enough experience they don't know
what sort of trick you're doing on them
but they do make lots of silly mistakes
so let's just start here let's say X
wants to win this fork let's just give a
proper example of forking and that X
wins with this fork so X will start here
and since o is a pretty nice player
he'll say that ok you didn't go for a
corner or a side or the center so that
means you're bad at this so then all
would just get really overconfident and
he'll just place his over there okay
next X will play over here Oh still
really thinks that he's a master of this
thing and he just plays over here okay
oh it doesn't realize it but if X were
to play here now you would have two ways
for him to win so X will play here and
now X can either place here or here in
his next turn and he would always win so
now there's zero possible ways for o to
win I guess for example o goes here X
place here in wins and let's just
recreate this quickly when this and
let's just say again oh there's this now
for example o will play here X will play
here and win so no matter what this fork
attack will always work against almost
always work against newer players and it
you really works it's a really good
tactic but thing is our computer as I
said is
it's smart enough or at least I didn't
program it because that would be a lot
of code to actually fork however it can
defend against support attacks I'm
wondering how does it defend against a
fork attack well let me just tell you
right now the way it defends is let's
just say it's going to look at all of
these corners and it'll check around
them if any two are filled up then just
fill up those corners immediately
so for example let's just say X is over
here o which it's a computer will
automatically go here because as you can
see taking the court says Center is its
top priority as long as there's no other
strategies possible so it'll take the oh
in the center and then what will happen
X will go over here trying to over smart
pickle or outsmart the computer but then
over around this and create this little
thing this means that these two are
basically wasted now they can't really
fork anymore you could also go like this
but then again it would go this and then
it's basically almost a tie game now and
as you can see o has also created a fork
oh I've gone here in one but it's just a
bit more fun to do this so as you can
see now there's a fork for oh he can
either go like this or like this so
let's just say he decides to go like
this and Oh will win no matter what here
so that really sums that up now in order
to explain the rest of this I don't want
to give you lots more examples so I'm
gonna do is I'm going to explain an
actual example game that I played with
the computer and I wanted to explain
exactly what the computer thought behind
every single move it did now let's get
started I'm X the computers Oh so as
tic-tac-toe convention says I will be
going first because I'm X so I always I
take the center first usually okay I
took the center now the computer is like
okay this i connect I can't use a
strategy it'll that's just out of the
picture so what should I do now I can't
take the center I should take a corner
so it picks this corner over here so
that's what the reasoning was
behind this corner they've picked after
that I decided to place an X over here
this allowed me to threaten an attack
this way
on a diagonal but then the computer
realized that and put an O there this
means that the computer found out that I
was about to win so it blocked me from
winning then what's gonna happen is I
just place an X here and at this point I
you I placed an X here in order to block
these two O's from meeting I did not all
realize that I had just created an
opening for me to win so what happened
the computer did realize that so it
tried to its best to block me over there
and so I actually wondered why didn't it
just go for this corner why did it have
to go up here then I found out that okay
there actually wasn't opening for me to
win and so it chose this so I I don't
win and then what happens is that I
threatened an attack like this over in
this way and then what happens is the o
decides to block here and then over here
so it becomes a tie game no one wins the
computer is amazing at this so now we
will be getting into the Mac part again
if you find any way to beat this please
mail me at tad you manage gmail.com my
mail will be in the description yeah
let's get to the Mac parts and you can
also comment it down those in the video
comments and yeah let's get to the Mac
part so welcome to the back part of the
video and now we will explaining the
code and giving a life's little demo so
now I will be giving you a demo and
let's start so as you can see this is a
blank UI and I'm just gonna start in the
center as most good tic-tac-toe players
do I guess start in the center the app
will automatically put it over here I'm
just gonna click over here now and it
the text that I'm about to win and it
blocks me from winning
because it doesn't want me to win of
course I'm gonna close it here again
blocks me from winning now there's no
way either of us could possibly win I
mean I could do a diagonal but of course
it's too smart and then of course this
will actually try to win but then I just
do that
and we're gonna draw so then I can just
continue reset let's just play one more
example game all right here as you can
see it went concentr immediately because
it really asked you and then it tried to
block me here I'm gonna block it here
it's going to try to well it just took
this corner because there was nowhere
else for it to go I mean it could have
gone when they here but it isn't smart
enough to do that yet as you can see
then we can block it yet but I mean this
app will always either end up in a draw
or a win for the computer so this is
pretty nice and easy but let me just you
know at the whiteboard I gave you that
little example game I'm just going to
recreate that here so you can actually
see the app doing it so let's just start
as you can see the first move that I did
was play in the center the app will
automatically play here next I played
over here threatening an attack over
here so that I could win but then the
computer blocks and also makes a way for
it to win on its next turn however I
block that and I create a little gateway
for me to win and I didn't even realize
this but the computer did so if place
down and oh here and block you from
winning next I place down an X here
threatening over here however in place
down and oh and as you can see this all
could either continue extend or I could
just place it here and we end in a draw
of course because the computer is smart
enough to know exactly what move to do
at what time so that we either end in a
draw or a win so now we can reset and
I'm going to continue with explaining
the code so as you can see we have
classroom control and we have 9 IB
outlets for each UI button these are all
UI buttons if you didn't know already
each one of these I guess ok
so apart from that we have our reset
button and output label also which I
will just quickly show to you this is
the output label this is the reset
button the reason we create IB outlets
for this because we need to hide and
show them next we have the game over
which
tells us if our game is over and we also
have our plays array or a dictionary
which is an INT dictionary which will
store all of our grids and their status
and if you just come over here quickly
you'll see that this is the entire
dictionary in its full form so there's 0
1 2 3 4 5 6 7 8 for each ID for each
little grid or block next we have a
timer this timer will set the correct
colors for each little square every 0.01
seconds that's like 0 1 what's after
milli it's forgot after 4 millions so
it's 1 millisecond basically and then
what it's every one millisecond it's
going to look at it and it's going to
say ok I'm sorry every 10 milliseconds
and so what it's gonna do every 10
milliseconds it's going to set each
correct color over here so this one will
be green this one will a black and some
lemon red because all those are so to be
read all greens are to be all acts as a
social green and all underscores this
will be black so then let's get back to
our buted load we are resetting our
entire grid being also set and then we
are setting the timer to every 10
milliseconds I will change the colors or
it will actually execute the function
change colors with no user info and make
sure our piece then we have our change
colors function as you can see pretty
simple it just sets the color for each
button depending on which button it is
then we have a button clicked function
this is called whenever we click on one
of these grid buttons and depending on
which button it is it'll take out the
button ID and it will essentially just
take that button ID set the it'll check
ok
if look if the grid the specific little
node at that ID already has an O do not
give it X if it's blank then give it X
so that's how it works over there that's
what we're doing then we're checking if
it placed the X then you want to reset
the view check for a win on both X and O
then do an AI turn and also reset the
view again the reset view just sets all
these texts for the buttons correctly as
you can see next we have the check for
win function or I have the check for win
function and so what we're checking if X
wins anyhow meaning they win by doing
this this this this this this or this or
this then it will tell us the X 1 and
just stop the game or it'll do the same
thing for o and it will also do the same
thing for a drop so it'll check if
there's no blank squares and no 1 1 then
it's a draw obviously after that we have
our reset view the reset mute function
sorry and inside of here we are checking
if the game is not over then we want to
set the correct title depending on what
Square is currently on meaning if
buttons 0 has the ID for plays 0 in the
dictionary then if that plays 0 is equal
to 0 then give it the O if it's 1 then
give it X or else just keep it the same
after that we had our reset clicked IB
action what that means is it will just
call the reset function and then the
reset function as you can see we are
just going for I in 0 8 meaning 1 2 9
and I guess you could call it plays I is
equal to negative 1 meaning we are
complete we are creating dictionary from
0 to 8 with each value being minus 1
then we are sending each buttons titles
to just underscores as as simple as it
possibly could be because these are just
little placeholders so that you can
actually see how it works
then we are just setting game over to
false we are hiding the reset button and
we are also hiding the output label then
what an AI does turn this is where
things get interesting and as you can
see from this Wikipedia page this is the
entire steps that Wikipedia gives you
and so I'm skipping two of these in my
program the first one is number 3 and
I'm also skipping number 6 so instead of
checking for basically I just check for
corners I don't check if I want to go to
the opposite corner I just check four
corners themselves that's it so that but
I mean it's still so far it works
perfectly it can only draw or win a game
so I don't really need to implement them
anyway so apart from that this is just
mainly a human strategy if you think
about it but for computers this is more
than enough to be drawn okay so the ad
does turn and also just one more little
piece of fact there's a variable called
current move which is the move that the
AI currently has in mind to do so it's
going to start by checking the last rule
it's when to check for an empty side if
there's an empty side the current move
will be one of those empty sides then
it'll check for empty corners if there's
an empty corner it'll be one of those
empty corners it'll continue like that
and keep sitting at the current move to
the best move that it thinks it's
currently possible then when it gets to
the end it will do that move and so if
the winged move is the best move that it
could do then it'll just the win if the
fourth is the best well it can't do a
fourth if blocking an opponent's fourth
is the best things we can do then it
will do that if the center is the best
if the empty corner or on the side of
the best it'll always do that so far
from that that's really all we have to
do there so as you can see first we are
creating the current move burial which
is a blank integer and then we are
playing the sides meaning we want to
check if there's an empty side and if
there is and you want to play to that
side so we want to check if plays one
meaning the first side is and
set it to 1 etc etc for all sides and
set them so that me want to check if
this core is available if there are of
course use the corners then we want to
check if the center is available if it
is music because that's usually a good
tactic then we want to block forks if we
detect a user trying to fork us well we
just block it so that they can't then we
want to check if the user can win and I
will tell you more about this code in
just a minute if they can then try your
best to block it and if you can win just
immediately win because obviously it's
gonna end the game no one else can win
and you've already won then we want to
actually play the move if there is a
move meaning it'll only play the move if
there is a move meaning if there's no
squares left to be filled it won't do
anything so here we are playing the move
so we're checking if let nothing is able
to current move meaning we have a move
then plays the current move is equal to
zero meaning set it to an O and then we
want to reset the view check for a win
and then you south of you again now as
you can see these two little if
statements are quite different from the
rest because these are using a flat
statements
let me explain them first of all let's
see block the user if they can win
basically this is going to set a
constant called win available to two in
our row which is a function I created
and it'll check if X has two in a row if
it does then you want to set the current
move to that when that's available for
them meaning it will try its best to
block it however if you can win meaning
there's two in a row for o then you want
to set the current move to the way that
you can actually win because that will
end the game and you will also one so
then we can actually play that move as
you can see I've already told you about
that code but let's see the two in a row
function as you can see this function
takes the players of string and the an
array as two as a dictionary of intent
and so this is pretty simple
I mean it's nice it's an integer or
dictionary and as you can see this is
how it's actually gonna look inside of
the program the reason I had this
dictionary is because I had a custom
array feature before but then I didn't
really use it so I just still have it
there and this will return an optional
aunt and my default this will return nil
and so what'll happen is if the player
is X then you want to check every single
possible almost every single possible
combination that X could have tuner like
this one this one or this one
and we want to do that for every single
one except for a few which I'll explain
later and then what's gonna happen is
we're also going to check for oh okay so
then that's there so we're checking
every single possible combination for a
two in a row
that could possibly be there and then
after that it just returns the blank one
so for example if let's say o has an
opening at 1 4 7 meaning that this and
this are occupied but this one is free
meaning we just draw it out for you
these two are occupied but this one is
free that means it will return 7 because
then we can move to 7 and win so that
just proves that that really understands
how it will have to use its moves and
then apart from that but it's really
simple and now if I were to run this one
once more we can just do one more sample
game let's just play a little bit more
smart this time so I want to play the
center so it doesn't get an opportunity
to attack me from the diagonal then I'm
going to play this corner then I went to
play on over here so it cannot beat me
then of course the plays over there for
some reason
oh yeah so it blocks me then I'm just
going to play over here item Li and play
over here as you can see it's a job
because the computer is so smart even
look human can't beat it and that just
means it's really smart so yeah that was
the app now let's good for the ending of
so the source code will be down in the
description below you can feel free to
run through that I didn't really tell
you yet
there might be a few witches with this I
have written tested this but if you can
find any glitches in this whatsoever
please leave it down in the comment
section below
you can also email me at Tai Chi manage
email comm my email will be in the
description below if you didn't
understand that and yeah if you send it
to me I may just feature your comment or
email on my next video because I mean I
want to tell people that you're pretty
smart that you found that glitch and
also you deserve it because I could not
find any glitches whatsoever with this
my family couldn't find it my friends
couldn't find it so that's pretty much
foolproof if you can I'll give you a
shout-out great and yeah that was that
source code will be down in description
feel free to run through it use it in
your own app I yeah subscribe feed to my
channel and you like my content you'll
see more of it like my video if you
liked it and yeah comment if you have
any suggestions or any questions you can
even email me at tad you mana at
gmail.com I'm email will also me down in
the description and that's it goodbye