python3简单易懂

# 求字符串GC-Ratio是多少
def func(s):
    res = 0
    for i in s:
        if i == 'A' or i == 'T':
            res += 0.5
        else:
            res += 1
    return res
while True:
    try:
        Ratio = 0
        p = ''
        D = input()
        n = int(input())
        #GC-Ratio最大的时候,将子序列存起来
        for i in range(len(D) - n + 1):
            s = D[i:i+n]
            if func(s) > Ratio:
                Ratio = func(s)
                p = s
        print(p)
    except:
        break