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DIY: Decode Ways

Explore how to decode strings of digits into corresponding letters using defined mappings from 1 to 26. Understand the constraints on valid groupings and implement a function to return the number of possible decodings. This lesson helps develop problem-solving skills applicable to coding interviews focused on string and dynamic programming challenges.

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 ...