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DIY: Decode Ways

Explore the Decode Ways problem in cyber security which involves decoding digit strings into letters using a specific mapping. Learn to implement a function that calculates the number of valid ways to decode a message, understanding key constraints like invalid leading zeros. This lesson builds skills in cryptography and message integrity relevant to coding interviews.

Problem statement

A message containing the letters from A-Z can be encoded into a string of numbers, using the following mapping:

'A' -> "1"
'B' -> "2"
...
'Z' -> "26"

To decode an encoded message, all the digits must be grouped and then mapped back into letters, using the reverse of the mapping ...