Feature #2: Detect Virus

Description

While studying different DNA samples, we observed that a certain virus consists of really long sequences of k distinct nucleotides. The virus infects a species by embedding itself into the species’s DNA. We are working on devising a test to detect the virus. The idea is to analyze the longest string that consists of, at most, k nucleotides from a species’s DNA.

We’ll be provided with a string representing a chromosome from the infected DNA and a k value supplied from a hidden function. Our task will include calculating the longest subsequence from the chromosome string that has k unique nucleotides.

Here is an illustration to better understand this process: