题解 | #DNA序列#
DNA序列
https://www.nowcoder.com/practice/e8480ed7501640709354db1cc4ffd42a
str1 = input()
n = int(input())
flag = 0
index = 0
for i in range(len(str1)-n):
s = str1[i:i+n] # 可以举个例子试一试
CG = s.count('C') + s.count('G')
if flag < CG / n:
flag = CG/n
index = i
print(str1[index:index+n])
