Solution: Decode Ways
Explore how to decode strings of digits into alphabetic representations using dynamic programming. This lesson guides you through analyzing encoded messages, breaking down the problem, and implementing an efficient solution by storing subproblem results. You'll learn to optimize time and space complexity to confidently solve variations of the Decode Ways problem.
We'll cover the following...
Statement
Given a string that has only positive digits, your task is to decode the string and determine the number of possible ways to decode it.
Consider the input string as an encoded message, where each digit in the string represents an alphabet from A to Z. For reference, let’s look at the mapping below:
"1" represents "A"
"2" represents "B"
"3" represents "C"
"26" represents "Z"
How to perform the decode operation?
To decode an encoded message, we have to check whether or not each digit in the string can be mapped onto the mapping above. There can be multiple ways to decode a string.
For example, the string "231012" can be decoded in the ...