题解 | DNA序列

string_dna = input()
n = int(input())
result = 0
result_dna = '' 
for i in range(len(string_dna)-n+1):
    c_num = string_dna[i:i+n].count('C')
    g_num = string_dna[i:i+n].count('G')
    if (c_num+g_num)/n > result:
        result = (c_num+g_num)/n
        result_dna = string_dna[i:i+n]
print(result_dna)

很简单