文本串加密和解密程序。一个文本串可用事先给定的字母映射表进行加密。例如，设字母映射表为：

　　　　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 g z q t c o b m u h e l k p d a w x f y I v r s j

　　　　则字符串“encrypt”被加密为“tkzwsdf”。

试写一个算法将输入的文本串进行加密后输出；

另写一个算法将输入的已加密的文本串进行解密后输出。-Text string encryption and decryption process. Available in advance of a text string given letter mapping table is encrypted. For example, suppose the letter mapping table: abcdefgh I jklmnopqrstuvwxyz ngzqtcobmuhelkpdawxfy I vrsj the string " encrypt"　is encrypted as " tkzwsdf" . Try to write an algorithm to input text string will be encrypted output　another write encrypted text string entered an algorithm will be decrypted output.