Python

判断是否有重复的字符串，若没有重复的字符串输出YES

def isDup(strs):
    lens = len(strs)
    i = 0
    while i < lens:
        j = i + 1
        while j < lens:
            if list(strs)[j] == list(strs)[i]:
                return False
            j += 1
        i += 1
    return True


str_in = input()
while str_in is not None:
    if isDup(str_in):
        print("YES")
    else:
        print("NO")
    str_in = input()