2012 Canadian Computing Competition, Stage 1
Problem J4: Big Bang Secrets
Sheldon and Leonard are physicists who are fixated on the the BIG BANG theory. In order to exchange secret insights they have devised a code that encodes UPPERCASE letters by shifting their letters forward.
Shifting a letter by S positions means to go forward S letters in the alphabet. For example, shifting B by S = 3 positions gives E. However, sometimes this makes us go past Z, the last letter of the alphabet. Whenever this happens we wrap around, treating A as the letter that follows Z. For example, shifting Z by S = 2 positions gives B.
Sheldon and Leonard's code depends on a parameter K and also varies depending on the position of each letter in the word. For the letter at position P, they use the shift value of .
For example, here is how ZOOM is encoded when K = 3. The first letter Z has a shift value of ; it wraps around and becomes the letter F. The second letter, O, has and becomes X. The last two letters become A and B. So Sheldon sends Leonard the secret message: FXAB
Write a program for Leonard that will decode messages sent by Sheldon.
The input will be two lines. The first line will contain the positive integer K (K < 10), which is used to compute the shift value. The second line of input will be the word, which will be a sequence of consecutive uppercase characters of length at most 20.
The output will be the decoded word of uppercase letters.
Sample Input 1
Sample Output 1
Sample Input 2
Sample Output 2
Point Value: 5
Time Limit: 2.00s
Memory Limit: 16M
Added: Feb 29, 2012
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