题解 | #DNA序列#
DNA序列
https://www.nowcoder.com/practice/e8480ed7501640709354db1cc4ffd42a
s = input()
N = int(input())
ls = []
for i in range(0,len(s)):
ls.append(s[i:i+N])
#print(ls)
lst = []
for i in ls:
if len(i) == N:
lst.append(i)
#print(lst)
ld = []
for i in lst:
ld.append((i.count('G')+i.count('C'))/len(i))
print(lst[ld.index(max(ld))])

