Advanced Sudoku Solving - Arrow Sudoku #3

hi there guys and welcome to another Sudoku flavored video uh today we'll be looking at Arrow Sudoku um so our Sudoku is a variant on the classic theme so it's still a regular Sudoku puzzle in that you need one through nine everywhere you can think of um but then there's also an extra constraint which we'll see as we go through uh this is the third puzzle I've done I think on the channel so hopefully it's um something that you guys are Vaguely Familiar with if you've seen any of those um but yes it is from the collection of puzzles uh published by the cracking the cryptic team top pair of puzzle solving experts who have their own YouTube channel and um well worth checking out links in the description um they solve puzzles much better than I do and they've been going for years and years so um yeah well worth checking them out um they've created this lovely collection of handcrafted puzzles with really nice logic um and uh yeah would definitely recommend picking up if this sort of thing interests you there's hundreds of puzzles available and they're a really fantastic excuse me there we go I thought I was going to be denied my sneeze there um right let's jump in shall we so um these apps are set up so that as you earn Stars by completing puzzles you unlock um access to the later puzzles at the same time so we are on to puzzle 42 um because they didn't release all at the same time this is our final one star difficulty puzzle for the arrow sudokus so we'll see how we get on um so what's the additional constraint when it comes to Arrow Sudoku well these arrows you can see here um uh the cell the nut the digit that you put in this cell has to be summed to by the digits along its Arrow so in this puzzle there are actually all three cell arrows but they don't have to be they could be two or more and um uh the uh what was I going to say oh yes and digits can repeat on an arrow so obviously the straight arrows like this you couldn't repeat a digit because it would break the rule of Sudoku about not repeating a digit in a row so these digits are all different however these digits aren't necessarily different these two could be the same digits that's perfectly allowable in the rules of Sudoku um and but these two would have to be different digits because obviously they're in the same box um yeah so you basically need to put the digits in so that they these three add up to that one um right so that's it let's get going um okay then the way to the usual way to start thinking about these is to well looking for long arrows makes sense and when I say long arrows I mean long Arrows with definitely different different digits so actually the fact that these could both be the same Arrow puts less pressure on this cell so for instance these cells have to be different so the minimum you could make these cells is one two and three and so that would add up to six so in fact we know that any three digits arrow that half that have to have different digits the minimum is going to be six so in fact I'm going to just start and be lazy and do this and just pop six seven eight nine so we know that they're going to be at least six in fact I can do quite a bit better than that because this cell sees this six this cell sees the same six and this cell sees that six and this cell also sees that six so in fact none of these can be a six so that's what I meant when I was being lazy so I just chucked in the 60 where I knew it was pointless now can we do better we can so that one actually can't be a nine so that's important for a reason I'll discuss in a bit this one can't be an eight or a nine so in fact that's our first digit that one must be a seven um this one can't be a seven or an eight that's seven or a nine because it sees them in the box so this in fact must be an eight and this one can't be a nine or a nine which is not as helpful um right it's gonna be a nine twice as well good for it okay so what do we know now about these three cells so these three cells they're different and they add up to seven in fact if you have three cells trying to make them add up to seven you can only do that in one way if the digits different um you have to it has to be a one two four collection um so one two three makes six one two four makes seven and you can't go lower than that um you couldn't have like two threes or whatever uh or two twos so um so there's definitely one two seven a one two four here and in fact that cell can't be a one because it sees that one and that one can't be one because this is out so that is a one these are a two four pair okay now now that's interesting because this cell whichever of those two numbers it is two or four will be in this rules it out of this arrow and as I've just said a seven needs to have a one two and a four so whatever whichever if I put a two here I can't put a 2 here if I put four here I can't put four here in either case this cell cannot be a seven so that must be an eight okay um and then this cell could still be either a seven or an eight so I can't do much better now okay so what do we know about eight so eight in three cells now there's two ways to make an eight not for three cells it can be a one two and five or it can be one three and four both of those have a one so whichever way around it is I know there's a one um in one of these three cells and in fact it can't be there of course because there's a one in that box so that so there's one here um interestingly then uh I can do the same logic here so there's definitely a one there and there's definitely a one here because the seven or an eight will definitely need a one either way okay what can we do next ah so in this box where can we put seven so in the middle box where the seven go well it's ruled out from these cells by the arrows not the Arrows by the sevens over here and here and then if we think about it why could we put seven in these three well actually you couldn't put seven on the Arrow because this Arrow this needs to add up to eight and we've got two more cells so you couldn't put seven one and zero that's not how Sudoku works so in fact that is a seven now as I said seven off of three cells has to be one two and four if those cells have to be have to be different unfortunately because this cell could be the same it doesn't give us as much sort of limit and we really want to limit things down to one or you know two options or one option it's obviously the best because in that becomes the answer um so this could be a few different things right so if these were both one this could be as big as a five uh they can't both do one to be fair because this cell sees that one in there and that so that is at least a two or a four if that's a four this would be a one two pair so yeah so that could be a H that's really lovely isn't it so this cell has to be either a two or a four it can't be a one uh it could be a two and then this would need to add up to five which is perfectly fine or it could be a four and this would need to add up to um three which again is perfectly fine however we've got exactly the same logic that we had applied to this arrow with this two four so whichever if it is it can't that number can't go down here which rules out a seven from this cell which is really nice so that is in fact an eight so that's cool I think um so yeah so this is either a one two pair or two three pair so if that's a two this needs to add up to five but there's a four in the box so it couldn't be one and four so that would have to be two and three um and it would actually have to go in this order or because of the three in that box there so that would rule that out um or it's if that's a four of these add up to three and in which case uh it is a could be a one or what it could be a one two pair so I haven't quite narrowed it down but I know and I do know there's a two whichever way around it is is definitely a two in these two boxes so I'll note that in the corner and then I've limited the possibilities in the cell excuse me I'm quite got over that cough yet I thought I had ah now interesting oh that's very interesting so what's the lowest this could be well if we do one one and two one one two okay well actually you couldn't do that could you because there can't be a one here so the lowest this could be is two two and one to be five so this could be a five but then it couldn't be six seven or eight so this could be a five or a nine laughs I wonder if I'm missing anything obvious before I start digging too okay yes just by Sudoku that has to be an eight so that's useful um yeah this could be a four wow okay that's really not very helpful is it well could it same thing that can't be a one that could be a one two pair though couldn't it uh so that could be five and again then it could be it couldn't be seven eight or nine so that is a five or a six okay does it have to be a one there does have to be a one doesn't there oh you can't unclick oh that's a bit annoying uh there definitely has to be a one here I think because what's the lowest you can go you can go two two two and three yeah which doesn't add up to five or six so it's definitely one here and in fact it's not there because of that one over there so there's a one here um maybe some just regular sudokuing right so there's a one in one of those two uh uh it doesn't have to be a one up there that's there I've got one's limited there there threes are not very restricted just yet fours it's definitely a four one of those two sevens well you can't put seven on an arrow not three digit Arrow anyway so yeah so the seven in this box actually just goes here okay so that was actually staring me in the face and similarly that must be the seven in the bottom box uh seven yeah it's quite a lot of freedom of seven sort of eight similarly you can't put an eight there so eights are limited to two cells there which mean they can't be here so there's an eight in one of those two sauces well uh what do we know about eight here it's one of these three that's not very useful yeah similarly up here and finally nines ah we can place a nine in that box that's nice uh that gives us lines restricted to those two cells that can't be a nine ah there we go so Nine's a restricted there which is a virtual nine in this column so we know we can't put another line in this in this row rather I should say so that's definitely not a note so that's a nine um oh in fact yes sorry look in this middle box where does nine go well it doesn't go there by the nines and the grid um so we have to put nine somewhere in here and it can't go on an arrow right I should have seen that very early so that is in fact a nine uh does that sort out add Nines It does because in the in this box you can't put a nine on the Arrow so nine has to go there that gives us nine there so hooray we are done on nines now this yeah nine on for three is quite is not very restricted at all hmm come on engage Brian ah no no I thought I had a thought and then I swiftly didn't have a thought any longer five and six uh okay yeah sorry yeah no I should have seen that I don't know why I missed that so eight in this box is restricted to two cells there which means that can't be the eight um similarly no not similarly oh well yeah okay so the reason I didn't see that before I did see the eights were here and then nine went in there didn't it so not my fault gov um camps yeah I'm not making much not making as much progress as I probably should be um can I be a four that's a four that would be a one three pair which would be totally fine this being a nine is really unhelpful it could be anything on this Arrow you need to average three it's not very helpful is it um I do feel like one that should be at some resolved I don't know automation there's a one star difficulty puzzle ah of course set that can't be a seven blind again so seven in this box is restricted because seven can't go there all there big by the sevens here and here and then also it can't go on the Arrow so that is a seven which sorts that out as a seven that's nice shorts that out as a seven and that out as an eight oh I wonder if we've just done some damage here so eights go there in that box sevens are done I think yeah okay so that's all the sevens um and we've got eight in a little X-Wing down there so we've done the big digits basically it's about six uh similarly six can't be on this Arrow can it so six is limited here yeah because it would be six one and one which you're not allowed to do you could do that on one of these arrows that could be six that could be one one six I mean it couldn't be because of these but you know what I mean um okay so in this box right I think we're making some progress finally so six and this box is limited then it can only go in one of these two places because of this and this excuse me winning out these cells you can't put the six in the error so that is a six um which puts uh six here and you can't put six on this Arrow because obviously the arrow itself needs to add to six so you'd have to have two zeros to accompany it which doesn't make sense so that's a six sixes in this column up here so that must be a six and in fact it is a 6 8 pair which is nice um is this useful it's difficult I mean even though you've got this additional degree of Freedom with these two potentially being the same it's still difficult to make a six right because if that's if that was the smallest that can be as a two facts I think it has to no sorry it can't be a two two and four are over there so the smallest could be a three and I think it has to be a three because the next available that is a five and that would ruin the arrow because then both of these would need to add to one so that is in fact three and I think that is quite big right because that gives us this being a five and we finally have some progress on these a arrows these eight these three arrows here I thought they would be really powerful instantly but they just weren't because you can't it's still you know it's either a one two and five or one three and four and yeah so it wasn't very helpful but this being a five has finally sorted this out so this is a one two pair which is useful because that then makes that a four and then we did some logic okay before didn't we so these two have to add up to three so that can't be a three so that is a one two pair which is nice it's not as nice as it could have been um what are we missing from this column this needs one two and three no five turn five unfortunately ah does that that looks no it doesn't lock it in because that could still be three four either side can it might be a one three four I was gonna say this must make this a one two five arrow but I don't think it does that could be a three four one yeah ignore me and my crazy ramblings yeah this puzzle's resisting okay it's also six these are a one this is also a one two pair ah and that gives us a one two pair in them in the column and so basically what that means is nowhere else on this column can there be a one or a two so that rules out the one from that cell so that is a one and that is a four which is a three so yeah so that that was what I was looking for and that's a two and that's a one right I think we've I think this is gonna solve this puzzle now I think we're basically done um although the proof will win pudding so that's the one that's a two that's a one that's a two yeah these arrows of tumbling like flies now um right there can't be a three on this eight arrow because of the threes there so this is a five two pair which we can resolve that's a five that's two that's a use me five I misread that pencil Mark as a three that's a four that's a two that is a five which means that these two add up to six and so the missing digit from the arrows are three um can we fill in any other threes we must be able to there's a three up there uh yes three down in this box is restricted by this three here so that must be a three these two have to add up to five and cannot have one so that is a one that is a two three pair ah yeah so so this is nice so there is one I've finally been able to show one arrow that does in fact have two threes on so that is a three three two Arrow which doesn't feel right in the world of Sudoku but it's perfectly acceptable perfectly acceptable um can we do any damage on sixes we can because there's a six in that box in that cell which then sorts out this six which sorts out this six which thoughts have this six oh my gosh absolutely flying on the sixes in fact yeah that was all of them blindly they just fell like dominoes that is a five uh uh to complete the Box that is a two to complete the row the column and the Box actually the box would have been easier to look at uh there's an eight in that cell there's an eight in that cell uh oh that's all the big numbers done six seven eight nine right so we are missing a two from this box we are missing a two from this box which must go there where does three go in this box it goes here here that's a five that's a five that's a four right let's go this one this puzzle was I I either I just missed some really obvious stuff early on or that was genuinely quite tough but either way completed it yes um happy with that that was fun uh it's a bit challenging not one star puzzle that was a genuinely tricky one but anyway uh thank you for watching if you have been I hope you enjoyed the video and I will see you in the next one thank you very much cheers

Channel: JimTheGamer

Views: 39

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Id: 8zykKTUANiU

Length: 23min 11sec (1391 seconds)

Published: Mon Jun 05 2023