题解 | #DNA序列#
DNA序列
https://www.nowcoder.com/practice/e8480ed7501640709354db1cc4ffd42a
s = input()
n = int(input())
r = 0
res = ''
for i in range(len(s)-n+1):
ratio = (s[i:i+n].count('C') + s[i:i+n].count('G'))/n
if ratio > r:
r = ratio
res = s[i:i+n]
print(res)
# sliding window
滑动窗口
，可以适当对关键信息加粗一点，比如关键技术、性能指标之类的。