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    "培训考核题"
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    "1.恺撒密码 \n",
    "\n",
    "描述：\n",
    "\n",
    "凯撒密码是古罗马凯撒大帝用来对军事情报进行加解密的算法，它采用了替换方法对信息中的每一个英文字符循环替换为字母表序列中该字符后面的第三个字符，即，字母表的对应关系如下：\n",
    "\n",
    "原文：A B C D E F G H I J K L M N O P Q R S T U V W X Y Z\n",
    "\n",
    "密文：D E F G H I J K L M N O P Q R S T U V W X Y Z A B C\n",
    "\n",
    "对于原文字符P，其密文字符C满足如下条件：C=(P+3) mod 26\n",
    "\n",
    "上述是凯撒密码的加密方法，解密方法反之，即：P=(C-3) mod 26\n",
    "\n",
    "假设用户可能使用的输入仅包含小写字母a~z和空格，请编写一个程序，对输入字符串进行凯撒密码加密，直接输出结果，其中空格不用进行加密处理。\n",
    "\n",
    "输入输出示例：\n",
    "\n",
    "输入: python is good\n",
    "\n",
    "输出: sbwkrq lv jrrg"
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    "2.利用字典结构统计每个单词出现的频率（出现的次数／总单词个数）\n",
    "str=’’’ He works ten hours a day, makes more than US  $98,000 a year, doesn't bother to take holidays,  dresses as the please.  He's never been happier and is looking for another job. This 33 - year-old white, university-educated person is the typical internet worker, according to a study by the industry standard, a San Francisco-  based news magazine.’’’"
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   "source": [
    "3.编程完成10到16进制换算并输出"
   ]
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