Prompt: The DNA sequence is composed of a series of nucleotides abbreviated as ‘A’, ‘C’, ‘G’, and ‘T’.

For example, “ACGAATTCCG” is a DNA sequence. When studying DNA, it is useful to identify repeated sequences within the DNA.

Given a string s that represents a DNA sequence, return all the 10-letter-long sequences (substrings) that occur more than once in a DNA molecule. You may return the answer in any order.

Example:

Input: s = "AAAAACCCCCAAAAACCCCCCAAAAAGGGTTT"
Output: ["AAAAACCCCC","CCCCCAAAAA"]

Input: s = "AAAAAAAAAAAAA"
Output: ["AAAAAAAAAA"]

Solution: This is a sliding window problem. The condition for the sliding window is that it needs to be a length of 10 characters. We need to count each unique window. In the end, we need to return all the unique windows that contain 2 or more counts.