DNA 序列中的重复字符串

Question

I am trying to solve the following problem

Problem All DNA is composed of a series of nucleotides abbreviated as A, C, G, and T, for example: "ACGAATTCCG". When studying DNA, it is sometimes useful to identify repeated sequences within the DNA.

Write a function to find all the 10-letter-long sequences (substrings) that occur more than once in a DNA molecule.

For that my solution is as below.

def repeated_dna_sequence(seq):
  # Gather length 10 substrings and remember as seen
  repeated_sub_str = set()
  seen = dict()

  i = 0
  while (i + 10 < len(seq)):
    sub_str = seq[i:i+10]
    if not sub_str in seen:
      seen[sub_str] = 1
    else:
      repeated_sub_str.add(sub_str)
    i += 1
  return repeated_sub_str

For the input sequence input_str = "AAAAACCCCCAAAAACCCCCAAAAAGGGTTT" , my code returns ['AAAAACCCCC', 'AAAACCCCCA', 'AAACCCCCAA', 'AACCCCCAAA', 'ACCCCCAAAA', 'CCCCCAAAAA'] . However for the same question with the same input string in leetcode problem the output is given as ['AAAAACCCCC', 'CCCCCAAAAA'] . If anybody sheds some light on this issue that would be very helpful.

Thank you.

Answer 1

There is a difference between your input and the leetcode input. This gives you more hits.

Your Input: AAAAACCCCCAAAAACCCCCAAAAAGGGTTT
Leet Input: AAAAACCCCCAAAAACCCCCCAAAAAGGGTTT