OJ Board

To say that the judge solution is implemented in backtracking is only half true. I tested my solution with plenty of randomly generated test cases. If backtracking with pruning based on updating the constraints let you through, I'd consider you lucky. I had to do a bit more than that. I ordered the ...

It's kind of odd that you quote me and deduce something which is nothing I indicated. So let me elaborate. So I can say, the main reason - we don't get certificate after tenth place is "It is very difficult to print certificate in short time"! No, you can't say that. The main reason you do...

The rule we follow, says: Teams that solve the median number of problems or higher will be ranked according to the most problems solved; teams solving less than the median number of problems will be acknowledged but not ranked. I think this is decent enough and we must not ask for a change. Usually ...

I feel a bit itchy

Try 7-8-4-6-10. The cost would be 2+10+4+35=51.

Hmm... I admit that the statement is not that clear. Md Kamruzzaman, the author of the alternate solution for this problem, had pointed out this anomaly with the statement before it was used for the contest. But I was reluctant to make any change. Misof is right, if I were too specific then it would...

Because that helps you to put it as a parameter of some other function. Here is an example: [c] #include <stdio.h> #include <string.h> int main() { char str1[100]; char str2[100]; char str3[100]; strcpy(str1,"First"); strcpy(str2,"Second"); strcpy(str3,"Third"); printf(...

Right.

That actually follows from our construction of the network. Our network is basically a multistage graph that you form for finding all possible LISs of a sequence. Before I start to make it more confusing, let me clarify through a picture: http://www.kmhasan.com/multistage.jpg We construct this multi...

I think my post lacked an illustration. If the following network fails to explain the idea, please let me know. I'd try to elaborate some more. http://www.kmhasan.com/lis.jpg We can construct this network for the sequence: A = <7,5,1,15,13,8,16,10,9> As you'd see, the length of the LIS is 3, and the...

I've got a few gmail invitations that I can distribute. If you're in need, send me a PM or an email.

You'd need a grammar to define the syntax of BASIC. Here's one that could help: http://www.devincook.com/goldparser/download/grammar/files/basic-64.zip . Then you can go through the documentations for Flex and Yacc. Both Flex and Yacc comes with most of the Linux distributions. If you're using windo...

Right. I admit that I should have stated the output limits. Sorry about that. I modeled this problem to a LIS problem. You see, if you are in (r1,c1) and you can go to (r2,c2) then r2>=r1 AND c2>=c1. So if you pick up coords of the garbages then you can find the Longest Increasing Sequences to know ...

Why do you need to use BigNumber for this problem? The problem statement clearly says:

You can assume that the output will always fit in a 64bit unsigned integer.

It may happen that for your implementation the intermediate results go out of that limit. But trust me there are ways to avoid that.

Spoiler follows: I run a IDS (Iterative Deepening Search) keeping track of the cells I visit while searching within a certain depth. If this track is kept, then we are not going to explore the cells in that depth again if it leads to unsuccessful searches. A preprocessing with BFS can make the solut...