See my HLD Implementation (Here) . CodeChef was created as a platform to help programmers make it big in the world of algorithms, computer programming, and programming contests. discussions Dragons' Den - Season finale double header starts Dec. 17 at 8PM (8:30NT) CBC Receive points, and move Discussion and debate are a huge component of learning and our aim has always been to provide a platform that lets you do just that. I was trying to solve Chef and dragon using merge sort tree. However, if a node is not on that path, we must have entered and then exited it before arriving at c. That means both its entr and exit are in the given range, and they will cancel each other out when summed. Sphere It was giving O(log(n))^2, so also as per constraint it should not pass. I also wrote a Heavy-Light solution and it only took 0.20s. Invitation to CodeChef June Cook-Off 2020. cook-off, cook119. Editorial of Codechef july long challenge 2020 Video Editorial|video solution Beginer friendly Editorial 1)Chef and Strings : CHEFSTR1 2)Chef and Card Game : CRDGAME 3)Ada King : ADAKING 4)Missing a Point : PTMSSNG 5)Chefina and Swaps : CHFNSWPS 6)Doctor Chef : DRCHEF 7)Chef and Dragon Dens … However, there are some restrictions, Chef can only glide from a higher den to a strictly lower den, i.e. so i want to know where my code was failing. Here are my solutions to few codechef problems. This polyline divides the set of points \{(x, z): 1 \le x \le N\} into two regions. Can you help me with this? My submission, Among other things, you are checking if p_b is an ancestor of p_c by literally climbing the tree, but that is too slow, I used 3 Segment Trees and Stack Trick to solve the question. You can imagine tracing the tree traversal with a continuous line, then unwrapping and flattening it out (seriously, draw a picture, it will help). if he glides from a den at p_i to a den at p_j , then h_i \gt h_j must hold. You are welcome to do so. To simplify things, let’s assume that b \leq c for all queries of the second type. A chef hopes to stir up some Dragon interest and bring his business to a boil. So, we now can build the journey with the following algorithm. It may also fetch you a CodeChef internship! Every testcase is giving right answer but still getting wa, Powered by Discourse, best viewed with JavaScript enabled, p_1 = (1,h_1), p_2 = (2, h_2), \ldots, p_N = (N, h_N), https://www.codechef.com/viewsolution/35511735, Chef can only glide from a higher den to a strictly lower den, i.e. days long monthly coding contest and the shorter format Cook-off and Lunchtime coding contests have prizes worth up to INR 20,000 (for Indian Community), $700 (for challenges that take place through-out the month on CodeChef. If we connect each point to its optimal previous, we end up defining a rooted tree (or rather, a forest). 6)Doctor Chef : DRCHEF https://youtu.be/fjkAuLzdM9U 7)Chef and Dragon Dens : DRGNDEN https://youtu.be/j8zA7xGXuOc Link to the code of all the Question: 1)Chef and Strings : CHEFSTR1 And suppose we have the mountain as 5 4 4 2 with tastiness as 6 7 4 3 respectively. We create an array flat, then set flat[entr[u]] = a[u] and flat[ext[u]] = -a[u]. Well, yes, but that should explain why it’s not passing the last two subtasks at least. in Point updates and path sum queries can be handled by flattening the tree, rudimentary heavy-light decomposition, etc. Use our practice section to better prepare yourself for the multiple middle and You can request someone to generate random tests for you to test locally. programming size and the likes. This range is what entr[b] and entr[c] keeps track of. Can someone tell me what mistake I had done or provide some testcase in which my solution is failing. Each point has a unique optimal previous, if it has one at all. choice. If you think that above codes are un-optmized or you want to add new problems solutions for HackerRank. Copying solutions for some score gains which is quite substancial is highly discouraged to do. Then, the value of the maximum possible journey is simply the sum of the values of all nodes on the path from b to c. What about when b > c? When you enter a node u, push u onto the stack. A “mountain range” can be modeled by a polyline in a 2D plane that passes through N points p_1 = (1,h_1), p_2 = (2, h_2), \ldots, p_N = (N, h_N), in this order, where h_i is a positive integer for each valid i. The path is 5 -> 4 -> 2 (4 being the one with the higher value), I was trying it out like this initially but it gave me a WA verdict, but when I changed it to the “4” near the destination, it got accepted. CodeChef - A Platform for Aspiring Programmers. I was getting all the self made testcases answer correct but i don’t know why on submission i was getting WA not even a single ac. However, there are some restrictions. CodeChef was created as a platform to help programmers make it big in the world of algorithms, computer programming, and programming contests.At CodeChef we work hard to revive the geek in you by hosting a programming contest at the start of the month and two smaller programming challenges at the middle and end of the month. Consider any optimal journey from p_b to p_c that does not include p_i. Then, we see that the sum of the values of the nodes on the path from b to c is equal to the sum of some consecutive range of “recursive calls”. Labs. I divided the array into sqrt(n) blocks and for each block calculated the maximum of that array and also stores 2 sets, 1 for iterating into decreasing index and another for iterating into increasing index from the maximum value of a block and then storing path in the set from prev block max value or next block max value depending on iterating direction. This range contains all the nodes that we visit before c. If it is on the path directly between b and c, then only its entr is in the range and not its ext, because we only exit each of those nodes after we are done with all its descendants (and c is one of them). Browse their menu and store hours. I will briefly discuss one method for solving this, which is by flattening the tree, since it is the simpler one of the two. Program should read from standard input and write to standard output.After you submit a solution you can see your results by clicking on the [My Submissions] tab on the problem page. Editorial of Codechef july long challenge 2020 Video Editorial|video solution Beginer friendly Editorial 1)Chef and Strings : CHEFSTR1 2)Chef and Card Game : CRDGAME 3)Ada King : ADAKING 4)Missing a Point : PTMSSNG 5)Chefina and Swaps : CHFNSWPS 6)Doctor Chef : DRCHEF 7)Chef and Dragon Dens … - mdamircoder/CodeChef-Solutions Apart from providing a platform for programming There is an \mathcal{O}(\log n)-per-query solution anyway that isn’t too different, so the bounds are fine. end of the month. Question: Why does this trick not work with range max or range min queries? to help Codechef-Solutions-C-Language Contributing. Chef can glide from point to point, and the total value of a journey is just the sum of the values of all points visited. The runtime is thus \mathcal{O}(\log n) (with Tree Flattening) or \mathcal{O}(\log^2 N) (with Heavy-Light Decomposition) per query. those who are new to the world of computer programming. Since all values are positive, a journey from b to c can always be improved if we can squeeze in another point to be visited. Warning. through your I don’t think so. CodeChef was created as a platform to help programmers make it big in the world of algorithms, computer programming, and programming contests.At CodeChef we work hard to revive the geek in you by hosting a programming contest at the start of the month and two smaller programming challenges at the middle and end of the month. he can only glide from a den at. Our programming And, instead of popping u from the stack, push -a[u]. up This reduces the problem then to finding the maximum possible value of all journeys that start at p_b and end at p_i. At CodeChef we work hard to revive the geek in you by hosting a Why does my implementation with Fenwick Tree give TLE on all TC’s? Try your hand at one of our many practice problems and submit your solution in the language competitions, CodeChef also has various algorithm tutorials and forum is it possible to get testcases?. Additional Links. When doing a point update on u, make sure to update both flat[entr[u]] and flat[ext[u]]. Maintain updates on both, and use the appropriate one when querying. I will provide my CodeChef Solution Codes here. How can we check if b is an ancestor of c? I did a euler tour of tree, at each entry I added the positive value of taste of node(+c) , and at exit negative of same value(-c). Each point p_i is initially assigned the value a_i. Question: What do you do for path queries from u to v where one is not the ancestor of another? We use cookies to improve your experience and for analytical purposes. 2: 195: July 14, 2020 Invitation to CodeChef July Long Challenge 2020. long-challenge. We also aim to have training sessions and discussions related to Simple—just create two different forests, one for left-to-right motion, and one for right-to-left motion. p_i is the point nearest p_c to its left that is higher up than it. Give some testcases on which it is failing. TLE because what if the heights are 4,5,6,7,8,9…so in worst case you are doing n jumps, we need less complexity than that. Below are the possible results: Accepted Your program ran successfully and gave a correct answer. There are two types of queries: For when b > c, create another rooted forest that represents motion in the other direction. CodeChef is a competitive programming community of programmers from across the globe. When you exit a node u, pop u from the stack. Community) and lots more CodeChef goodies up for grabs. Levi Roots, who was nominated for best reggae singer at the 1998 Mobo awards, persuaded TV entrepreneurs to invest £50,000 in … So, let’s try to determine a point that we for sure will visit on the way from p_b\to \dots \to p_c. So, we just check if entr[b] <= entr[c] and ext[c] <= ext[b] (actually it doesn’t matter if we use entr[c] or ext[c] for each check). I want to know where is my sol for Chef and Dragon Den going on plz? if he starts travelling in the direction of decreasing, Chef cannot travel through solid mountain, i.e. Handling point updates and path sum queries can easily be maintained using your favorite tree data structure—you could flatten the tree, or use Heavy Light, or whatever you want. c-plus-plus. Our programming contest judge accepts solutions in over 55+ same here bro. We call i the optimal previous because we can show that it is always optimal to include p_i in Chef’s journey. Research You must process Q queries. For our problem, we may get a forest, so create a dummy node 0 that is root of all our trees. (Let’s say we want to travel from 1-4) Why can’t we glide to the first “4” which has a higher value and then go directly to 2, we won’t be going through the 2nd “4” would we? So, Chef is always traveling with increasing x-coordinates. How about the path queries? Lang : Contest Top Ranks (CodeChef’s Long, Cook-Off, LTIME, or any contest hosted with us) 300 + Bonus (Bonus = n – contest rank, where ‘n’ is 21 for long contest and 11 for short contests) 2: Bug Finder: 50 – 1000 (depending on the bug severity). At CodeChef we work hard to revive the geek in you by hosting a programming contest at the start of the month and two smaller programming challenges at the middle and end of the month. the region that contains the x-axis. Put yourself up for recognition and win great prizes. contests. Here is another way to visualize this. CodeChef - A Platform for Aspiring Programmers. Share among friends so can i have 150 subscribers.You have only one day left share fast guys ..After 150 subscribes i will share my github link The names of those files will be as of the coded names used in CodeChef page. Please Suggest , How can I Improve my both solution , HLD and Eulers both. If b is an ancestor c, then the sum of all nodes on the path from b to c is just the sum of flat[entr[b]] until flat[entr[c]]. Take part You consent to our cookies if you continue to use our website. How can answer those queries quickly? But Henry and Will, who needed funding to help grow the business further (they want 80,000 people signed up by the end of 2018), decided to apply for Dragons’ Den. Then just compare the maximum values between blocks to check if path exist between two blocks. Here time complexity would be 0(n) where 'n' is the length of the array.. Add a comment at the bottom of the file with time complexity. Thunder Bay, ON: How much are they asking for? languages. Thanks I unable to score 100pts.This is my euler Implementation(Here) . Our tree has n+1 vertices, so each of the integers from 0 to 2n+1 is associated with a particular node, on either entry or exit. Start at c, then visit its optimal previous, then visit its optimal previous, and so on, until we end up at b. If you go through with the \mathcal{O}(\log^2 n)-per-query solution, it becomes your responsibility to make the constant factor not-too-bad. CodeChef is a competitive programming community, CodeChef uses SPOJ © by Sphere algorithms, binary search, technicalities like array CodeChef was started as an educational initiative in the year 2009 by Directi, an Indian software company. And Raise a pull request mentioning this issue for any problem.. [Codechef | July long challenge 2020 | Chef and Dragon Dens | DRGNDEN | Solution] The “solid” part of the mountain range is the “bottom” region, i.e. Research Global If there is a score for the problem, this will be displayed in parenthesis next to the checkmark. But then, by the same argument, we know we have to pass through the optimal previous of i, and so on. CodeChef uses SPOJ © by Sphere Research Labs It is always optimal to visit as many points as possible on the journey. I used set for only that purpose. programming programming If there is a score for the problem, this will be displayed in parenthesis next to the checkmark. Determining the optimal previous of all points can be done in \mathcal{O}(N) using a stack. We maintain a global timer which starts at 0, and maintain two arrays entr and ext, corresponding to the entry and exit time of each node. Chef can glide from point to point, and the total value of a journey is just the sum of the values of all points visited. A chef who sang to impress investors on BBC Two's Dragons' Den has said his supermarket deal is a "dream come true" as his sauce hits the shelves. For instance, take this coding problem move-zeroes-to-end.js. I had a small doubt regarding the statement: It’s mentioned that gliding is allowed so that you can “touch the polyline itself” as long as you don’t go thought the mountain. algorithms, computer programming, and programming QTREE with path sum, instead of max-edge. Apart from its monthly coding contests for the community, CodeChef has many initiatives for Schools, Colleges and Women in competitive programming. That’s equivalent to c being a descendant of b, i.e. of Order food delivery and take out online from Dragon Chef Restaurant (10706 79 Ave, Grande Prairie, AB T8W 0G9, Canada). If we don’t end up at b, then the journey is impossible. CodeChef: Competitive Programming Platform [A-] [A+] It is a global competitive programming platform which supports over 50 programming languages and has a large community of programmers that helps students and professionals test and improve their coding skills. CodeChef was created as a platform to help programmers make it big in the world of Can you tell me why I am getting WA. the CodeChef ranks. That’s completely wrong way to go, because there could be multiple Include/Exclude heights in a block. CodeChef is credited with hosting the India regionals of the … CodeChef Goodies; CodeChef Workshops; ICPC; IOI; Frequently Asked Questions; About Us; Home » Practice(medium) » Chef and Dragon Dens » Priyank Kumar Gupta » Submissions. I also used the same technique. Let i be the greatest integer less than c such that i < c and h_i > h_c, i.e. contests. Below are the possible results: Accepted Your program ran successfully and gave a correct answer. No way to get the official tests. We are okay with letting \mathcal{O}(\log^2 N) solutions pass if they are optimized (both the setter’s Heavy-Light and Tree Flattening solution finish in 0.20s). Read our Privacy Policy and Terms to know more. Now, we perform a DFS tree traversal starting from the root. I am not able to find testcase on which my solution is failing. Who are they? My basic idea is to do it using the idea of the MO algorithm. 2. © 2009 Directi Group.All Rights Reserved. I tried first using HLD, unable to get more than 10pts. Consider the stack of recursive calls for our DFS. if he glides from a den at, Chef can only glide in one direction and never look back, i.e. Contribute to insomniac12/CodeChef development by creating an account on GitHub. Program should read from standard input and write to standard output.After you submit a solution you can see your results by clicking on the [My Submissions] tab on the problem page. If anybody knows how to get testcases please tell me. Here is where you can show off your computer programming skills. I haven’t looked at your code too closely so there’s probably something else causing it to TLE on the first subtask. our 10 Tai Chi Chef. My sol: https://www.codechef.com/viewsolution/35511735, @shisuko There should be bit relaxation in constraint, instead of n=2100000 , n should be equal to 100000. We’ll just touch the edge which is allowed. Call i the “optimal previous” of c. Since no other point between i and c is higher than h_c, we know it is always possible to travel from p_i to p_c. Preparing for coding contests were never this much fun! c exists in the subtree of b. Question: Suppose you should start at b but you can choose whatever ending point c that you want. But I am receiving WA on other test cases except sample one. We can then improve the score of that journey by first passing through p_i and then ending on p_c. 3: Contest Hosting: 50: 4: Random Laddus: 200: 5 Then we’ll go to 2. I maximum got 45 points. For sum I was able to do it in O(log(2n)) but for update it takes 4O(log(2n)) after a bit optimization , it was still taking 2O(log(2n)). contest at the start of the month and two smaller programming challenges at the Peng Yu & Luba Cargill: Where are they from? terminator125's SUBMISSIONS FOR DRGNDEN. Contribute to jainaman224/codechef development by creating an account on GitHub. CodeChef was designed and created to help programmers acquire the tools to improve their own skills and abilities. When you reach c, the only nodes on the stack are those on the path from b to c. Now, instead instead of pushing u onto stack, push a[u]. LabsIn order to report copyright violations of any kind, send in an email to copyright@codechef.com. This way I got list of size (2n) .Made a segment Tree over it.From Euler entry and exit point , I was able to identify ,if the one node is ancestor of one or not.If yes , the sum of starting point of a to starting point of b in segment tree gives the total taste from a to b else -1. Checking if it is possible to get from p_b to p_c is a matter of checking if b is an ancestor of c in its tree. We can maintain point updates and range sum queries with either a segment tree or a Fenwick tree, giving \mathcal{O}(\log n) time per query. 6)Doctor Chef : DRCHEF https://youtu.be/fjkAuLzdM9U 7)Chef and Dragon Dens : DRGNDEN https://youtu.be/j8zA7xGXuOc Link to the code of all the Question: 1)Chef and Strings : CHEFSTR1 Judith Fetzer from Montreal, Que., pitches her family-friendly meal plan subscription service. Now, note that the entr and ext of all nodes in the subtree of some u must appear between entr[u] and ext[u], which can be more easily visualized if you have a picture of the traced path. Why? The direction of decreasing, Chef can only glide in one direction and never look back, i.e my for. Where one is not the ancestor of c computer programming skills ending on p_c and great! Size and the likes Long chef and dragon dens codechef coding contests for the community, CodeChef has many initiatives for Schools, and... Just touch the edge which is allowed den to a strictly lower,... Well, yes, but that should explain why it ’ s assume that \leq! By the same argument, we now can build the journey is impossible you do for path from... Multiple programming challenges that take place through-out the month on CodeChef was as. We now can build the journey with the following algorithm Include/Exclude heights a., if it has one at all p_c to its optimal previous because we can show off your programming. On plz we connect each point p_i is initially assigned the value a_i 4 2! Consent to our cookies if you continue to use our practice section to better prepare yourself for the multiple challenges. Fenwick tree give TLE on all TC ’ s not passing the last subtasks! Of algorithms, binary search, technicalities like array size and the.... And programming contests it is always optimal to include p_i in Chef ’ s to. Community, CodeChef has many initiatives for Schools, Colleges and Women competitive... I, and use the appropriate one when querying we have the as... The appropriate one when querying two different forests, one for right-to-left motion you to locally... My code was failing can build the journey and Terms to know where code... Policy and Terms to know where my code was failing un-optmized or you want to add new problems for... Last two subtasks at least need less complexity than that but that should explain why it ’ s wrong. Entr [ b ] and entr [ b ] and entr [ c keeps. Track of problems solutions for some score gains which is quite substancial is highly discouraged to do not pass then... In worst case you are doing n jumps, we end up at b then... { O } ( n ) using a stack me why i am receiving WA on test... Can only glide in one direction and never look back, i.e put yourself up for recognition and great. From Montreal, Que., pitches her family-friendly meal plan subscription service in 10. Previous, we perform a DFS tree traversal starting from the stack you consent our! A higher den to a strictly lower den, i.e and programming contests if there is competitive. I had done or provide some testcase in which my solution is failing represents motion in the direction. Get a forest, so also as per constraint it should not pass we have to through... Can choose whatever ending point c that you want to know more the point nearest p_c its. Solve Chef and Dragon den going on plz through p_i and then ending on.! Well, yes, but that should explain why it ’ s passing! Chef ’ s not passing the last two subtasks at least my implementation Fenwick. Heavy-Light solution and it only took 0.20s we also aim to have sessions! And entr [ b ] and entr [ b ] and entr [ b ] and [! Section to better prepare yourself for the community, CodeChef has many initiatives Schools! Started as an educational initiative in the year 2009 by Directi, an Indian software company the root is.! That should explain why it ’ s completely wrong way to go, because there could multiple... Case you are doing n jumps, we need less complexity than that rooted tree ( or,... & Luba Cargill: where are they from p_b to p_c that does include. Range max or range min queries if anybody knows How to get than! The appropriate one when querying be as of the mountain range is what entr [ b ] entr. Giving O ( log ( n ) ) ^2, so also as constraint! Many initiatives for Schools, Colleges and Women in competitive programming community chef and dragon dens codechef! Also wrote a Heavy-Light solution and it only took 0.20s right-to-left motion tree starting! Well, yes, but that should explain why it ’ s.! On the journey is impossible also wrote a Heavy-Light solution and it took... Can request someone to generate Random tests for you to test locally you are doing n jumps, we can. Laddus: 200: 5 Here are my solutions to few CodeChef problems 6 4! Recursive calls for our problem, we know we have to pass through the CodeChef ranks regions. Computer programming, and move up through the CodeChef ranks your solution in the world algorithms. On p_c, etc mountain as 5 4 4 2 with tastiness as 6 7 3... Initially assigned the value a_i give TLE on all TC ’ s equivalent to c being a descendant of,! Determining the optimal previous, if it has one at all and the likes there be... One is not the ancestor of another our many practice problems and submit your solution in the year by., one for right-to-left motion the second type and Eulers both a Heavy-Light solution it... Is an ancestor of c set of points \ { ( x, z ): 1 \le \le! Optimal previous because we can then improve the score of that journey by first passing through p_i and then on. The set of points \ { ( x, z ): 1 \le x \le }! The second type created to help programmers acquire the tools to improve your experience and for analytical.! Through-Out the month on CodeChef a unique optimal previous of i, and so on where... Community, CodeChef has many initiatives for Schools, Colleges and Women in competitive programming community of programmers from the! And one for right-to-left motion the following algorithm also aim to have training sessions discussions...: Suppose you should start at p_b and end at p_i is the... Was trying to solve Chef and Dragon den going on plz: are... Range is what entr [ c ] keeps track of solution, HLD and Eulers both can someone. ’ ll just touch the edge which is allowed > h_c, i.e a boil get testcases tell... Implementation ( Here ) however, there are some restrictions, Chef can only glide from a higher to. That b \leq c for all queries of the coded names used in CodeChef.! Pop u from the root discussions related to algorithms, binary search, technicalities like size! The stack complexity than that possible results: Accepted your program ran successfully gave. Popping u from the root be displayed in parenthesis next to the.! \To p_c be the greatest integer less than c such that i < c and h_i >,. Was started as an educational initiative in the year 2009 by Directi, an Indian software company \... Coding contests for the problem, this will be displayed in parenthesis next to the.! Push -a [ u ] to get testcases please tell me solution in direction. We also aim to have training sessions and discussions related to algorithms, computer programming skills create two different,... What do you do for path queries from u to v where one not! For sure will visit on the journey is impossible all our trees plan subscription service all... In one direction and never look back, i.e using merge sort.! Platform to help programmers make it big in the world of algorithms binary... Way from p_b\to \dots \to p_c bottom ” region, i.e someone to generate Random tests for to... Of b, i.e up for recognition and win great prizes Terms to know is! Node 0 that is root of all our trees the last two subtasks least! As of the mountain as 5 4 4 2 with tastiness as 6 7 4 3 respectively this not... Range is what entr [ c ] keeps track of programmers acquire the tools to improve their own and! At, Chef is always traveling with increasing x-coordinates merge sort tree call i optimal. Now can build the journey x \le N\ } into two regions do chef and dragon dens codechef using the of! Programming languages you tell me what mistake i had done or provide some in. Testcases please tell me what mistake i had done or provide some testcase in which my solution is failing 5... To chef and dragon dens codechef July Long Challenge 2020. long-challenge is allowed by flattening the tree, rudimentary Heavy-Light decomposition etc... Solve Chef and Dragon den going on plz i also wrote a Heavy-Light solution and it took. Chef ’ s not passing the last two subtasks at least the globe the set of points \ { x! Which is quite substancial is highly discouraged to do two regions the previous! They from could be multiple Include/Exclude heights in a block visit as many points as possible on journey!: July 14, 2020 Invitation to CodeChef July Long Challenge 2020. long-challenge test cases sample... Point that we for sure will visit on the way from p_b\to \dots p_c! And for analytical purposes, but that should explain why it ’ s the heights are in! 2020. long-challenge ) using a stack when querying for left-to-right motion, and move up through the CodeChef....