### slow.coder's blog

By slow.coder, history, 3 years ago,

In competitive programming I believe every programmer has his/her favorite books (or blogs or reading materials) from which s/he learns(or learned or is learning) a lot. According to your opinion what are the best learning materials in your CP life and you would suggest as a programmer to another programmer must to read.

Thank you. Happy Learning !!!

[Although I am not so much experienced but I have some favorites and one of them I think, "Competitive Programming 3 by Steven & Felix.]

• +2

By slow.coder, history, 4 years ago,

I've tried this and everything is fine for STAR3CAS — THE WEIRD STAIRCASE. I've used recursive dp to solve this problem but it is getting WA. What are some critical IO from your side. Help please... Thanks :)

• -8

By slow.coder, history, 4 years ago,

I'm totally new to game theory. I think this problem 847 — A Multiplication Game can be solved using minimax algorithm. But I can't design the losing position for this problem. This problem may solve by finding pattern CF post, but I want to solve this problem with the concept of game theory (minimax algorithm). Any hint(how to think about losing position) for this problem form u, programmers??? :)

• -8

By slow.coder, history, 6 years ago,

Hello coders!!!

I'm new user of Ubuntu 14.04, and I have installed code blocks 13.12 on it. But I have found that Abbreviation plugin is not installed here. If you have any idea to solve this problem(How to install Abbreviation plugin?) then please help me.

• +5

By slow.coder, history, 6 years ago,

SPOJ Problem: Tiling a Grid With Dominoes

In short: You are given the value of N, now determine in how many ways you can completely tiled a 4xN rectangle with 2x1 dominoes.

We can solve this problem using DP technique, when the recurrence relation is:

f[n] = f[n - 1] + 5 * f[n - 2] + f[n - 3] - f[n - 4];


Here is a great explanation: count the ways to fill a 4×n board with dominoes. Thanks to draughtsman for providing such a wonderful tutorial link. :)

• -4

By slow.coder, history, 6 years ago,

[Here, I will list different effective tips and techniques with explanation. If you have any tips or techniques to share then you can comment(Your name will be added with problem). I will add that as a new problem. And give your explanation if you have any for unexplained problems.]

#### 2. Problem 2(Tiling 4xN grid with 2x1 block)

• +14

By slow.coder, history, 6 years ago,

LuckyLand Lottery is a problem directly related to Josephus problem!!!

In short:

There are N peoples (N > 0) arranged in a loop (peoples are numbered from 1 to N) so that 1st person comes after Nth person. In each lottery round the 2nd person wins starting from random number P (0 < P <= N), then next round starts from that position where it was ended before (winners will not consider for next rounds). Given the value of N and P. You need to find the person who wins at last.

AC soln:

ans = N - 1's complement of(N) + P - 1
if(ans > N)
ans = ans mod N


I don't know how does it work...

Have you any Explanation to describe this soln?

• 0

By slow.coder, history, 6 years ago,

In short, You are given the value of N, now determine in how many ways you can completely tiled a 3xN rectangle with 2x1 dominoes. Here is a possible soln: Algorithmist — UVa 10918. My question is, how is the recurrence defined? Here,

********   AA*******   AA******   A*******
******** = BB******* + B******* + A*******
********   CC*******   B*******   BB******
f(n)   =  f(n-2)   +  g(n-1)  +  g(n-1)


Isn't it possible as:

********   AA*******   AA******   AA******
******** = BB******* + BA****** + AA******
********   CC*******   BA******   BB******
f(n)   =  f(n-2)   +  f(n-2)  +  f(n-2)


or like others....(actually I want to know it). How can I define such type of recurrence?

Actually I want to know, what type of thinking should I keep in mind while defining recurrence for Tiling Block problem???