Practice Decode Ways II
Read the task, work through the examples, and check your approach against the constraints. Use the original LeetCode task for coding and submissions.
Problem Statement
Decode s using A = 1, B = 2, through Z = 26. Divide the full string into valid one- or two-digit codes; a code cannot start with zero. Each * independently represents any digit from 1 through 9, never zero. Count all resulting valid decodings, including the choices represented by stars, and return the count modulo 10^9 + 7.
Source: Decode Ways II on LeetCode. Use the original task for its coding environment and submissions.
Examples
# Example 1
Input
s = "*"
Output
9
# Example 2
Input
s = "1*"
Output
18
# Example 3
Input
s = "2*"
Output
15
Constraints
1 <= s.length <= 10^5
s[i] is a digit or '*'.
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