CCC '04 J4 - Simple Encryption

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Points: 5
Time limit: 2.0s
Memory limit: 256M

Problem type
Canadian Computing Competition: 2004 Stage 1, Junior #4

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. (B G, C H, …, T Y, U Z, V A, …, Z 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 the 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 header.

 A C T B A N A N A P E E L

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 letters 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:

 A C T B C G A P T P G X L

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 uppercase characters.

Input Specification

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 Specification

Output the encoded message on a single line.

Sample Input 1

ACT
BANANA & PEEL

Sample Output 1

BCGAPTPGXL

Sample Input 2

TRICKY
I LOVE PROGRAMMING!

Sample Output 2

BCWXONKFOTKKFZVI

• commented on May 18, 2024, 8:16 p.m.

alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" u can always use the index as how much the letter shift, because A index is 0 B index is 1 C index is 2 etc. but remember this is a string not a list.

• commented on Feb. 6, 2024, 3:12 p.m.

can the key have lowercase letters in it?

• commented on Aug. 28, 2021, 10:08 p.m. edit 3

Python's ord ("letter(upcase)") with chr(The number after ord(or any change))is a good choice for this question.

>>> ord("A")
65
>>> chr(65)
"A"
• commented on Feb. 21, 2022, 2:34 p.m.

so is isalpha() method...;)

• commented on June 5, 2021, 6:28 p.m. edited

Here are a few tips:

• To shift letters, change ASCII values. Create a variable to shift letters.
• To make the block/table with the words, enter the characters row by row.
• Do not print out spaces in the encrypted word.
• commented on Jan. 3, 2021, 10:30 p.m.

Is the code supposed to encrypt values like exclamation marks in the sample input 2?

• commented on Jan. 4, 2021, 4:27 a.m.

From the problem description:

To encode the message, you take the original message, remove everything but the alphabetic characters, and [...]

• commented on July 7, 2020, 4:41 p.m. edit 3

The letter-number mappings, as a Python dictionary:

{1: 'A', 2: 'B', 3: 'C', 4: 'D', 5: 'E', 6: 'F', 7: 'G', 8: 'H', 9: 'I', 10: 'J', 11: 'K', 12: 'L', 13: 'M', 14: 'N', 15: 'O', 16: 'P', 17: 'Q', 18: 'R', 19: 'S', 20: 'T', 21: 'U', 22: 'V', 23: 'W', 24: 'X', 25: 'Y', 26: 'Z', 'A': 1, 'B': 2, 'C': 3, 'D': 4, 'E': 5, 'F': 6, 'G': 7, 'H': 8, 'I': 9, 'J': 10, 'K': 11, 'L': 12, 'M': 13, 'N': 14, 'O': 15, 'P': 16, 'Q': 17, 'R': 18, 'S': 19, 'T': 20, 'U': 21, 'V': 22, 'W': 23, 'X': 24, 'Y': 25, 'Z': 26}

• commented on April 2, 2022, 6:34 p.m.

Isn't it wrong cause A should be 0? Doesn't that mean B = 1 and so on?

• commented on Nov. 21, 2020, 3:11 a.m. edited

You can also just do ord(letter) - 96. This brings the letter 'a' to 1 - 'b' to 2 - and so on.

• commented on July 17, 2021, 6:09 p.m.

You can also just do ord(letter) - ord("a") + 1 or ord(letter) - ord("A") + 1

• commented on April 30, 2020, 12:17 a.m.

if i have completed this problem, how can i check other people's submissions?

• commented on April 30, 2020, 9:43 p.m.

Click on all submissions or best submissions. Choose one, click view and then view source.

• commented on Jan. 10, 2020, 7:11 p.m.

Remember ascii values are a thing.