C :: W's Cipher
Time Limit: 1 Second Memory Limit: 32768 KB
Weird Wally's Wireless Widgets, Inc. manufactures an eclectic assortment of
small, wireless, network capable devices, ranging from dog collars, to pencils,
to fishing bobbers. All these devices have very small memories. Encryption algorithms
like Rijndael, the candidate for the Advanced Encryption Standard (AES) are
demonstrably secure but they don't fit in such a tiny memory. In order to provide
some security for transmissions to and from the devices, WWWW uses the following
algorithm, which you are to implement.
Encrypting a message requires three integer keys, k1, k2, and k3. The letters
[a-i] form one group, [j-r] a second group, and everything else ([s-z] and underscore)
the third group. Within each group the letters are rotated left by ki positions
in the message. Each group is rotated independently of the other two. Decrypting
the message means doing a right rotation by ki positions within each group.
Consider the message the_quick_brown_fox encrypted with ki values of 2, 3 and
1. The encrypted string is _icuo_bfnwhoq_kxert. The figure below shows the decrypting
right rotations for one character in each of the three character groups.
Looking at all the letters in the group [a-i] we see {i,c,b,f,h,e} appear at positions {2,3,7,8,11,17} within the encrypted message. After a right rotation of k1=2, these positions contain the letters {h,e,i,c,b,f}. The table below shows the intermediate strings that come from doing all the rotations in the first group, then all rotations in the second group, then all the rotations in the third group. Rotating letters in one group will not change any letters in any of the other groups.
Input
All input strings contain only lowercase letters and underscores(_).
Each string will be at most 80 characters long. The ki are all positive integers
in the range 1-100.
Input consists of information for one or more encrypted messages. Each problem
begins with one line containing k1, k2, and k3 followed by a line containing
the encrypted message. The end of the input is signalled by a line with all
key values of 0.
Output
For each encrypted message, the output is a single line containing the decrypted string.Sample Input
2 3 1 _icuo_bfnwhoq_kxert 1 1 1 bcalmkyzx 3 7 4 wcb_mxfep_dorul_eov_qtkrhe_ozany_dgtoh_u_eji 2 4 3 cjvdksaltbmu 0 0 0
Sample Output
the_quick_brown_fox abcklmxyz the_quick_brown_fox_jumped_over_the_lazy_dog ajsbktcludmvSubmit
Source: Mid-Central USA 2001