Problem 7
Description
This problem was asked by Facebook.
Given the mapping a = 1, b = 2, ... z = 26
, and an encoded message, count the number of ways it can be decoded.
For example, the message 111
would give 3
, since it could be decoded as aaa
, ka
, and ak
.
You can assume that the messages are decodable. For example, 001
is not allowed.