Feature #2: Detect Virus
Explore how to detect a virus in DNA sequences by calculating the longest substring containing k distinct nucleotides. This lesson teaches the sliding window technique with two pointers and a HashMap to efficiently track unique characters, helping you understand practical applications in computational biology and coding interviews.
We'll cover the following...
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:
Solution
Since we want to return a substring from a specific window over the original string, we can use a sliding window approach to accomplish this efficiently. We’ll use two pointers, left and right, to denote ...