03 Complementing a Strand of DNA

Problem

In DNA strings, symbols 'A' and 'T' are complements of each other, as are 'C' and 'G'.

The reverse complement of a DNA string ss is the string scsc formed by reversing the symbols of ss, then taking the complement of each symbol (e.g., the reverse complement of "GTCA" is "TGAC").

Given: A DNA string ss of length at most 1000 bp.

Return: The reverse complement scsc of ss.

Sample Dataset

AAAACCCGGT

Sample Output

ACCGGGTTTT

方法一

def reverse(seq):
    dict = {'A': 'T', 'C': 'G', 'T': 'A', 'G': 'C'}

    revSeqList = list(reversed(seq))                #['T', 'G', 'G', 'C', 'C', 'C', 'A', 'A', 'A', 'A']
    revComSeqList = [dict[k] for k in revSeqList]  # ['A', 'C', 'C', 'G', 'G', 'G', 'T', 'T', 'T', 'T']
    revComSeq = ''.join(revComSeqList)             # ACCGGGTTTT
    return revComSeq

seq = 'AAAACCCGGT'

print (reverse(seq))