I see. I like the Stack Overflow link Shreeyash provided. I also like this tutorial on Codeforces: Counting problems from A to B.

Here are my thoughts and observations on it:

• You should think of digit DP problems as j...

The best bit manipulation tutorials are Fun with Bits – topcoder and Bit Manipulation - HackerEarth. Although I haven't tried any of these problems myself, HackerRank seems to have a good collection of problems on bit manipulation.

I find bit manipulation to be useful quite rarely. B...

It is dynamic programming on the digits of a number. It involves problems like this one Codeforces problem 489C.

Also, this might be useful : http://stackoverflow.co...

I am unable to understand the solutions of this problem. Can you please provide similar problems? Maybe solving other problems that require similar technique will help me.

Here is the hard version of the problem - Młodzieżowa Akademia Informatyczna (MAIN)

Same problem, with k <= n <= 3000, So O(n k^2) isn't gonna pass.

Yes this version of your solution seems essentially the same. And it also seems as general as mine which uses a helper array, i.e. I don't think there are problems that your version without th...

Where can I find hints or tutorial... :)

However I get TLE in last 2 subtasks. O(N*log(N)*log...

Instead of taking the center B, can't we sort the co-ordinates and then take the leftmost co-ordinate A while sweeping from right to left.

Then, find the number of co-ordinates with y-coordin...

You can also compress the coordinates and use a normal BIT, which would be much easier.

Full Solution:

• At first get the shortest path tree rooted at S using Dijkstra.Now what we observe is if those edges w...

I am still unable to figure out the solution from Keshav's Hints. Would be grateful if someone expanded those hints.

Thanks.

I'll add hints to problems that I've solved (the few ones that I could manage :P).