题解 | #DNA序列#

str1 = input() num = int(input()) times = 0 l = [0] c = 0 for i in range(len(str1)): if i+num < len(str1): count_cg = str1[i:i + num].count('C') + str1[i:i + num].count('G') if count_cg > c: c=count_cg l[0]=str1[i:i + num] else: count_cg = str1[i:].count('C') + str1[i:].count('G') if count_cg > c: c=count_cg l[0]=str1[i:] print(l[0])