Easy Problemscountinglinearstring
Decode Ways
A digit string was produced by mapping 'A' to '1' through 'Z' to '26' and concatenating the codes with no separators between them. Count how many original letter messages could have produced the given digit string.
Do this lesson first: climbing stairsThe full breakdown and animated table for this problem are still being written. In the meantime, run the four questions on it yourself — that is the whole exercise.