CCC '04 J4 - Simple EncryptionView as PDF
2004 Canadian Computing Competition, Stage 1
One of the simplest ways of coding a message is to do a letter shift.
For example, if you shift the letters in the original message by then
A in your original message becomes
F in the coded message. (
E). To decode the message, you simply need to shift back by the same number.
A slightly trickier encryption uses a keyword to determine the amount of the shift. Suppose you were using a keyword
ACT. To encode the message, you take the original message, remove everything but the alphabetic characters, and form the message into a block that has the same width as the keyword. Here is a sample message to encrypt:
BANANA & PEEL
The blocked version of the message is shown below with the keyword
ACT as a
Now, the message is encoded using a letter shift. However, this time it is not
a uniform shift, it will depend upon the keyword letter at the top of the
column. If the letter at the top of the column is an
A, then the letters in
that column are not shifted. If the letter is a
B, then the letter in that
column shift by , and so on. In the example, the letters in the third column
will shift by since the
T is the th letter of the alphabet.
The encoded message is:
You will write a program that will accept a keyword and a string to be encoded. The keyword will never have more than characters. The message will always be given in all upper case characters.
The first line of input consists of the keyword. The second line of the input is the message to be encoded. The keyword length will never exceed characters. The total message length also will never exceed characters.
Output the encoded message on a single line.
Sample Input 1
ACT BANANA & PEEL
Sample Output 1
Sample Input 2
TRICKY I LOVE PROGRAMMING!
Sample Output 2
CCC problem statements in large part from the PEG OJ