过滤无用词汇程序。规则如下： 1. 能接受的字符是：字母 数字 标点符号 , . " 还有无用的符号 @#￥ 2. 对于敏感信息的词语是不分大小写的。 3. 要注意滤去可能在敏感词汇的中间出现的一些空格（比如要滤去lv, 输入l v时要辨认出来并滤去）。 4. 若有用信息（字母，数字）中间夹这无用信息（非字母，数字，标点符号），也要辨认出并滤去。假如敏感词汇是mz, 那么输入 m &# z也要滤去,但是输入 m1，z不用滤去。 现在要过滤的信息有L4和 Fd和D26这3个词，而且接受输入的字符串长度为20个字符。-Filter useless vocabulary program. The rules are as follows: 1. Acceptable characters are: alphanumeric punctuation, "There are useless symbols# ¥　2 words for sensitive information is not case-sensitive. Filtered may be in the sensitive some spaces in the middle of words (for example, to filter out lv, out to identify the input lv and filtered). if the use of information (letters, digits) sandwiching these useless information (non-letters, numbers, punctuation ), as well as identify and filter out sensitive words mz, then enter the m &# z is also filtered, but the input m1, z is not filtered. to filter L4 and Fd and D26 3 word, and accept the input string length is 20 characters.