Feature #4: Ways to Decode Message

Implementing the "Ways to Decode Message" feature for our "Network" project.


We are developing a cryptanalysis tool for simple ciphers. Each letter in the alphabet is assigned a specific code in this cipher— for example, 1 for A, 2 for B, and so on.

Unfortunately, without additional information, we can’t uniquely decipher some encrypted messages. For example, does the ciphertext 123 represent ABC (a 1, followed by a 2 and a 3), or does it represent AW (a 1 followed by a 23) or LC (a 12 followed by a 3)? To decipher an encrypted message, all the digits must be grouped and then mapped back into letters, using the reverse of the mapping above (there may be multiple ways of doing this).

We are given a ciphertext, c, in the form of a string of only digits. Our task is to return the number of possible plain texts.

Note: c contains only digits and may contain leading zero(s).

The following examples may clarify these requirements:

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