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An analysis of the 12 balls problem from perspective of Information and coding theory.

Problem: Given 12 balls/coins where all are identical save one such that the odd ball can be either lighter or heavier than other normal balls. We are given a beam balance that we can use for weighing to tell which of the two pans is heavier or are balanced. Our task is to find the odd ball in minimum weighing (different question can be to do so in 3 weighing). …

Consider a setting in which you have to share a secret among a group of participants such that a fixed no of participants are needed to recover it. The secret is divided into parts, giving each participant his own unique part.


Divide the secret S(for ex Nuclear launch codes) in to n pieces of data s1…. sn such that :

  1. Knowledge of k or more pieces of S allows the secret to be recovered.
  2. Knowledge of k-1 or fewer pieces of S makes it impossible to recover the secret S.

The threshold scheme can be written as (k,n) i.e at…

Exploration of counterfeit coin problems using Information Theory.An interesting question whose solution eludes if some key observations are not made. Analysis of the question will provide some key insights for application of Information Theory to such kinds of problems as a whole.

Problem: Given 3 pairs of coins such that each pair is uniquely marked and in each pair there is a fake coin which is lighter than perfect coin. Find all the fake coins with 2 weighing of the balance i.e coins are A{A1, A2}, B{B1 ,B2} & C{C1,C2}. Problem Source. …

An interview question that caught me completely off guard.

Q. Consider a infinite square field in which you are standing at origin of the coordinate system. The field is populated with some trees that you are allergic to, such that the trees are point sized and are placed on integer coordinates tree(x,y) where x,y ∈ set of I. You have to escape from the field in straight line without touching any tree.

Ans: In an initial look at the problem it seems completely impossible to escape the field as it is an infinitely large field and the gut feeling says…

I am a software engineer with background in both Computer Science and Electrical Engineering. I have special interest in Human Computer Interaction as I believe it has very strong potential to assist people with sensory disabilities and put bluntly its cool.

Occasionally, we all experience moments in our life that can be compared to a crippling punch to liver. These moments transform our day to day life into one with purpose and character, defining both our past and our future. Ever since I was a child I always wanted to join the Indian Army as I grew up during the…

Few words about ENTROPY and its applications

  • Entropy always increases.
  • Entropy represents the diversity of internal distribution of system.
  • Entropy is a function of state of system dependent only on initial and final states.
  • Information theory provides results that are independent of mechanism.

Problem: There is a gang of 256 people whose leader the CIA wants to apprehend, they send two undercover agents A and B to join the gang.
A goes deep in the gang and gets into the inner circle. A’s position in the inner circle makes him privy to a lot of information as well as the leader…


Reach for the sky

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