0639-decode-ways-ii.adoc

639. Decode Ways II

{leetcode}/problems/decode-ways-ii/[LeetCode - Decode Ways II^]

A message containing letters from A-Z is being encoded to numbers using the following mapping way:

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

Beyond that, now the encoded string can also contain the character '*', which can be treated as one of the numbers from 1 to 9.

Given the encoded message containing digits and the character '*', return the total number of ways to decode it.

Also, since the answer may be very large, you should return the output mod 10⁹ + 7.

Example 1:

Input: ""
*Output: 9
Explanation: The encoded message can be decoded to the string: "A", "B", "C", "D", "E", "F", "G", "H", "I".

Example 2:

Input: "1*"
Output: 9 + 9 = 18

Note:

1. The length of the input string will fit in range [1, 10⁵].

2. The input string will only contain the character '*' and digits '0' - '9'.

link:{sourcedir}/_0639_DecodeWaysII.java[role=include]