Problem 42525. Vigenere cipher - be like Sherlock Holmes!
You're a young detective. Every detective needs a function to decrypt a vigenère cipher. It's a modification of a caesar cipher.
Let's talk more about the algorithm:
- Every letter is a number. A=0, B=1, C=2, (...), Z=26
- Output should be presented in capital letters.
- Use ONLY letters. Without interpunction, spaces, etc
- Function has two arguments: encrypted text and key (both are strings). Your output will present a decrypted text. Let's show it on easy example from http://en.algoritmy.net/article/45623/Vigenere-cipher
Ciphertext : CTMCCD, Key : Cat
C – C = 2 – 2 = 0 = A
T – A = 19 – 0 = 19 = T
M – T = 12 – 19 = 19 = T
C – C = 2 – 2 = 0 = A
C – A = 2 – 0 = 2 = C
D – T = 3 – 19 = 10 = K
decrypted word: ATTACK
It's quite simple,right? Good luck!
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6 Comments
you should add a test case like GrantII does in his 'divisible by X' problems...
http://www.mathworks.com/matlabcentral/cody/problems/42408-divisible-by-6
thanks for advice! done! :)
Your testsuite is still incomplete. I recommend you to include cases where Ciphertext and Key both contain upper and lower case letters
Please kindly note that your test case 3 (a='az' b='za' y_correct='zz') is wrong. If you re-score all solutions, I think none of them would pass this test case. However, you may need to re-score multiple times because ind = randi(3) does not necessarily yield ind = 3.
thanks, I missed that mistake. it should be ok right now.
"A=0, B=1, C=2, (...), Z=26"
Shouldn't Z be 25?
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