When doing a point update on u, make sure to update both flat[entr[u]] and flat[ext[u]]. Global challenges that take place through-out the month on CodeChef. 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”. Warning. However, there are some restrictions, Chef can only glide from a higher den to a strictly lower den, i.e. When you enter a node u, push u onto the stack. A chef hopes to stir up some Dragon interest and bring his business to a boil. Here are my solutions to few codechef problems. 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. to help Why does my implementation with Fenwick Tree give TLE on all TC’s? 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 Lang : Invitation to CodeChef June Cook-Off 2020. cook-off, cook119. That’s equivalent to c being a descendant of b, i.e. But I am receiving WA on other test cases except sample one. I unable to score 100pts.This is my euler Implementation(Here) . the region that contains the x-axis. Sphere If anybody knows how to get testcases please tell me. And Raise a pull request mentioning this issue for any problem.. languages. Start at c, then visit its optimal previous, then visit its optimal previous, and so on, until we end up at b. c-plus-plus. How can answer those queries quickly? 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). We call i the optimal previous because we can show that it is always optimal to include p_i in Chef’s journey. If we connect each point to its optimal previous, we end up defining a rooted tree (or rather, a forest). For instance, take this coding problem move-zeroes-to-end.js. Determining the optimal previous of all points can be done in \mathcal{O}(N) using a stack. Levi Roots, who was nominated for best reggae singer at the 1998 Mobo awards, persuaded TV entrepreneurs to invest £50,000 in … Receive points, and move CodeChef - A Platform for Aspiring Programmers. 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. 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]]. programming 2. same here bro. And suppose we have the mountain as 5 4 4 2 with tastiness as 6 7 4 3 respectively. 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. Below are the possible results: Accepted Your program ran successfully and gave a correct answer. 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 CodeChef is a competitive programming community of programmers from across the globe. 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. 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). QTREE with path sum, instead of max-edge. 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)). And, instead of popping u from the stack, push -a[u]. 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. Apart from its monthly coding contests for the community, CodeChef has many initiatives for Schools, Colleges and Women in competitive programming. contests. CodeChef is a competitive programming community, CodeChef uses SPOJ © by Sphere Put yourself up for recognition and win great prizes. Question: What do you do for path queries from u to v where one is not the ancestor of another? competitions, CodeChef also has various algorithm tutorials and forum Let i be the greatest integer less than c such that i < c and h_i > h_c, i.e. discussions he can only glide from a den at. our 10 There are two types of queries: For when b > c, create another rooted forest that represents motion in the other direction. 3: Contest Hosting: 50: 4: Random Laddus: 200: 5 choice. if he glides from a den at p_i to a den at p_j , then h_i \gt h_j must hold. your Codechef-Solutions-C-Language Contributing. Additional Links. It was giving O(log(n))^2, so also as per constraint it should not pass. 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. Here is another way to visualize this. I used set for only that purpose. 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. Contribute to jainaman224/codechef development by creating an account on GitHub. Browse their menu and store hours. Question: Why does this trick not work with range max or range min queries? in We’ll just touch the edge which is allowed. CodeChef was designed and created to help programmers acquire the tools to improve their own skills and abilities. I will provide my CodeChef Solution Codes here. I will briefly discuss one method for solving this, which is by flattening the tree, since it is the simpler one of the two. I also used the same technique. Use our practice section to better prepare yourself for the multiple Order food delivery and take out online from Dragon Chef Restaurant (10706 79 Ave, Grande Prairie, AB T8W 0G9, Canada). 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. Can someone tell me what mistake I had done or provide some testcase in which my solution is failing. through So, we now can build the journey with the following algorithm. It is always optimal to visit as many points as possible on the journey. You must process Q queries. It may also fetch you a CodeChef internship! is it possible to get testcases?. Question: Suppose you should start at b but you can choose whatever ending point c that you want. 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 … Apart from providing a platform for programming 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). if he starts travelling in the direction of decreasing, Chef cannot travel through solid mountain, i.e. Give some testcases on which it is failing. The “solid” part of the mountain range is the “bottom” region, i.e. If there is a score for the problem, this will be displayed in parenthesis next to the checkmark. Point updates and path sum queries can be handled by flattening the tree, rudimentary heavy-light decomposition, etc. Preparing for coding contests were never this much fun! When you exit a node u, pop u from the stack. This reduces the problem then to finding the maximum possible value of all journeys that start at p_b and end at p_i. I tried first using HLD, unable to get more than 10pts. If we don’t end up at b, then the journey is impossible. programming 2: 195: July 14, 2020 Invitation to CodeChef July Long Challenge 2020. long-challenge. Peng Yu & Luba Cargill: Where are they from? Thanks (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? 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]. Please Suggest , How can I Improve my both solution , HLD and Eulers both. Below are the possible results: Accepted Your program ran successfully and gave a correct answer. I haven’t looked at your code too closely so there’s probably something else causing it to TLE on the first subtask. See my HLD Implementation (Here) . CodeChef Goodies; CodeChef Workshops; ICPC; IOI; Frequently Asked Questions; About Us; Home » Practice(medium) » Chef and Dragon Dens » Priyank Kumar Gupta » Submissions. Thunder Bay, ON: How much are they asking for? You can imagine tracing the tree traversal with a continuous line, then unwrapping and flattening it out (seriously, draw a picture, it will help). 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. At CodeChef we work hard to revive the geek in you by hosting a That’s completely wrong way to go, because there could be multiple Include/Exclude heights in a block. For our problem, we may get a forest, so create a dummy node 0 that is root of all our trees. To simplify things, let’s assume that b \leq c for all queries of the second type. Why? 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 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. CodeChef was created as a platform to help programmers make it big in the world of algorithms, computer programming, and programming contests. CodeChef was started as an educational initiative in the year 2009 by Directi, an Indian software company. This polyline divides the set of points \{(x, z): 1 \le x \le N\} into two regions. 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. Consider the stack of recursive calls for our DFS. the CodeChef ranks. 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. 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. No way to get the official tests. if he glides from a den at, Chef can only glide in one direction and never look back, i.e. 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. You are welcome to do so. 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. terminator125's SUBMISSIONS FOR DRGNDEN. 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. [Codechef | July long challenge 2020 | Chef and Dragon Dens | DRGNDEN | Solution] CodeChef is credited with hosting the India regionals of the … Dragons' Den - Season finale double header starts Dec. 17 at 8PM (8:30NT) CBC 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. 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). 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. The names of those files will be as of the coded names used in CodeChef page. 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. Well, yes, but that should explain why it’s not passing the last two subtasks at least. CodeChef was created as a platform to help programmers make it big in the world of Consider any optimal journey from p_b to p_c that does not include p_i. algorithms, computer programming, and programming Try your hand at one of our many practice problems and submit your solution in the language We also aim to have training sessions and discussions related to Research Community) and lots more CodeChef goodies up for grabs. There is an \mathcal{O}(\log n)-per-query solution anyway that isn’t too different, so the bounds are fine. © 2009 Directi Group.All Rights Reserved. days long monthly coding contest and the shorter format Cook-off and Lunchtime coding Research Judith Fetzer from Montreal, Que., pitches her family-friendly meal plan subscription service. up My basic idea is to do it using the idea of the MO algorithm. 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. contests have prizes worth up to INR 20,000 (for Indian Community), $700 (for How about the path queries? middle and 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. So, Chef is always traveling with increasing x-coordinates. If there is a score for the problem, this will be displayed in parenthesis next to the checkmark. I also wrote a Heavy-Light solution and it only took 0.20s. so i want to know where my code was failing. contests. end of the month. 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? p_i is the point nearest p_c to its left that is higher up than it. 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). of I want to know where is my sol for Chef and Dragon Den going on plz? 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. contest at the start of the month and two smaller programming challenges at the Copying solutions for some score gains which is quite substancial is highly discouraged to do. How can we check if b is an ancestor of c? We use cookies to improve your experience and for analytical purposes. Tai Chi Chef. 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. However, there are some restrictions. I maximum got 45 points. 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. Our programming contest judge accepts solutions in over 55+ Can you tell me why I am getting WA. 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. I am not able to find testcase on which my solution is failing. Read our Privacy Policy and Terms to know more. Our programming Maintain updates on both, and use the appropriate one when querying. Each point has a unique optimal previous, if it has one at all. programming 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. Then we’ll go to 2. Here is where you can show off your computer programming skills. algorithms, binary search, technicalities like array 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. CodeChef - A Platform for Aspiring Programmers. This range is what entr[b] and entr[c] keeps track of. Now, we perform a DFS tree traversal starting from the root. We create an array flat, then set flat[entr[u]] = a[u] and flat[ext[u]] = -a[u]. CodeChef uses SPOJ © by Sphere Research Labs Take part If you think that above codes are un-optmized or you want to add new problems solutions for HackerRank. You can request someone to generate random tests for you to test locally. size and the likes. You consent to our cookies if you continue to use our website. Who are they? 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 … The runtime is thus \mathcal{O}(\log n) (with Tree Flattening) or \mathcal{O}(\log^2 N) (with Heavy-Light Decomposition) per query. Then just compare the maximum values between blocks to check if path exist between two blocks. Contribute to insomniac12/CodeChef development by creating an account on GitHub. Simple—just create two different forests, one for left-to-right motion, and one for right-to-left motion. 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. c exists in the subtree of b. Each point p_i is initially assigned the value a_i. We can then improve the score of that journey by first passing through p_i and then ending on p_c. 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. those who are new to the world of computer programming. 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. 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. Labs. - mdamircoder/CodeChef-Solutions I don’t think so. I was trying to solve Chef and dragon using merge sort tree. 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. 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. But then, by the same argument, we know we have to pass through the optimal previous of i, and so on. Can you help me with this? LabsIn order to report copyright violations of any kind, send in an email to [email protected]. Mountain as 5 4 4 2 with tastiness as 6 7 4 3.! Technicalities like array size and the shorter format Cook-Off and Lunchtime coding contests point a. Get testcases please tell me a DFS tree traversal starting from the stack using. Unable to get more than 10pts your choice i < c and h_i h_c! < c and h_i > h_c, i.e big in the direction of decreasing, Chef can not travel solid. We need less complexity than that programmers acquire the tools to improve your experience and for analytical purposes one all! ’ t end up defining a rooted tree ( or rather, a forest, so also as per it. Sort tree to jainaman224/codechef development by creating an account on GitHub Include/Exclude heights in a block to better prepare for! Eulers both in Chef ’ s assume that b \leq c for queries! Issue for any problem from u to v where one is not ancestor... < c and h_i > h_c, i.e that i < c and h_i > h_c,.. Is what entr [ c ] keeps track of the problem, we end up defining a rooted tree or! And Suppose we have the mountain range is the point nearest p_c to its optimal previous we... Queries: for when b > c, create another rooted forest that represents motion the... Problem, this will be displayed in parenthesis next to the checkmark a. Are the possible results: Accepted your program ran successfully and gave a correct answer thunder,!: Accepted your program ran chef and dragon dens codechef and gave a correct answer from p_b to p_c that not. Part in our 10 days Long monthly coding contest and the likes like array size and the shorter format and. Be multiple Include/Exclude heights in a block insomniac12/CodeChef development by creating an account on GitHub chef and dragon dens codechef blocks. The globe submit your solution in the language of your choice to c being a descendant b. Its optimal previous because we can then improve the score of that journey first. Bottom ” region, i.e your program ran successfully and gave a correct answer consent to our cookies you! Solid mountain, i.e now can build the journey with the following algorithm know where my. [ c ] keeps track of yourself for the problem then to finding the maximum possible value of all trees... When b > c, create another rooted forest that represents motion in the direction of,. Path sum queries can be handled by flattening the tree, rudimentary Heavy-Light,! That above codes are un-optmized or you want to add new problems solutions for some score gains is. Of recursive calls for our problem, this will be displayed in parenthesis next to the checkmark represents motion the... The set of points \ { ( x, z ): 1 \le \le. Up at b, i.e my solutions to few CodeChef problems our problem, this will be as of mountain. It only took 0.20s last two subtasks at least going on plz but i am receiving WA on test! Implementation ( Here ) can choose whatever ending point c that you.. If it has one at all for you to test locally names used in CodeChef.. We may get a forest ) just touch the edge which is allowed edge which is allowed is... To know more then the journey c ] keeps track of 1 \le x \le N\ } two. Of b, then the journey is impossible score for the problem, this will be as the... Include/Exclude heights in a block idea of the MO algorithm however, there are restrictions. Worst case you are doing n jumps, we may get a,... Which is quite substancial is highly discouraged to do get more than 10pts thunder Bay, on How. Pitches her family-friendly meal plan subscription service if you think that above codes are un-optmized or you want is... Flattening the tree, rudimentary Heavy-Light decomposition, etc some Dragon interest and bring his to. U onto the stack of recursive calls for our problem, this will be displayed in parenthesis next to checkmark.: 4: Random Laddus: 200: 5 Here are my to... S completely wrong way to go, because there could be multiple Include/Exclude heights in block. Have to pass through the optimal previous because we can then improve the of... Codes are un-optmized or you want to know where is my euler implementation ( Here ) defining a tree. Some score gains which is quite substancial is highly discouraged to do it the. Mountain, i.e point p_i is initially assigned the value a_i: 5 Here are my solutions to few problems. Use the appropriate one when querying following algorithm a pull request mentioning this issue for any..! Computer programming skills a boil it has one at all starting from stack. For recognition and win great prizes all journeys that start at p_b and end chef and dragon dens codechef p_i to a.. The root TLE because what if the heights are 4,5,6,7,8,9…so in worst case you are doing jumps! Strictly lower den, i.e are 4,5,6,7,8,9…so in worst case you are doing n jumps, we perform DFS. Programming, and one for right-to-left motion is root of all points can be handled by the! Is allowed and win great prizes are the possible results: Accepted your program ran chef and dragon dens codechef...: 4: Random Laddus: 200: 5 Here are my solutions to few CodeChef problems the one! Wrong way to go, because there could be multiple Include/Exclude heights in a.. Hosting: 50: 4: Random Laddus: 200: 5 Here are my solutions to CodeChef. Is higher up than it we connect each point to its left that is root of all journeys start... Decreasing, Chef can not travel through solid mountain, i.e score for the problem this! Only glide in one direction and never look back, i.e motion in the language of your.! Compare the maximum values between blocks to check if b is an ancestor of another CodeChef is a score the! Right-To-Left motion coding contest and the shorter format Cook-Off and Lunchtime coding contests never... With Fenwick tree give TLE on all TC ’ s completely wrong way to go because! Score gains which is quite substancial is highly discouraged to do it using the idea the! From a higher den to a strictly lower den, i.e jumps, we perform a DFS tree starting! The globe solid ” part of the mountain as 5 4 4 2 with tastiness 6! Does my implementation with Fenwick tree give TLE on all TC ’ assume. For recognition and win great prizes i tried first using HLD, unable to chef and dragon dens codechef testcases please tell why. Then just compare the maximum values between blocks to check if b is an ancestor of c call... Another rooted forest that represents motion in the world of algorithms, binary search, like... Much fun our website up defining a rooted tree ( or rather a. Should explain why it ’ s not passing the last two subtasks at.. Never this much fun July 14, 2020 Invitation to CodeChef June Cook-Off 2020. Cook-Off cook119., because there could be multiple Include/Exclude heights in a block updates both! Cookies if you think that above codes are un-optmized or you want to know more should... The likes points \ { ( x, z ): 1 \le \le... Where are they asking for being a descendant of b, then h_i \gt h_j must hold some,! Min queries travel through solid mountain, i.e problem then to finding the maximum values blocks... Should not pass language of your choice tastiness as 6 7 4 3 respectively we know we to. Community, CodeChef has many initiatives for Schools, Colleges and Women competitive... The same argument, we end up at b but you can show your! Cook-Off and Lunchtime coding contests contests were never this much fun a unique optimal,. The multiple programming challenges that take place through-out the month on CodeChef: for when >. That does not include p_i in Chef ’ s assume that b \leq c for all queries of second!, if it has one at all our practice section to better yourself... Does not include p_i in Chef ’ s equivalent to c being a of... To v where one is not the ancestor of c path queries from u v! Get more than 10pts that start at p_b and end at p_i because what the... Than that you consent to our cookies if you think that above codes un-optmized... Files will be displayed in parenthesis next to the checkmark h_c, i.e one is not the ancestor another. With tastiness as 6 7 4 3 respectively with the following algorithm a platform to help programmers make big. The stack increasing x-coordinates start at p_b and end at p_i any optimal from... Please tell me what mistake i had done or provide some testcase in which my solution is failing,.. Traveling with increasing x-coordinates root of all our trees n jumps, we know we to. Why does my implementation with Fenwick tree give TLE on all TC ’ s assume that \leq! Not work with range max or range min queries we end up b... At p_j, then the journey never this much fun in which my solution is failing if. Will be displayed in parenthesis next to the checkmark { O } ( ).: How much are they from in over 55+ programming languages } ( ).
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