A message containing letters from A-Z can be encoded into numbers using the following mapping:
'A' -> "1"
'B' -> "2"
...
'Z' -> "26"
To decode an encoded message, all the digits must be grouped then mapped back into letters using the reverse of the mapping above. There may be multiple ways. For example, "11106" can be mapped into:
- "AAJF" with the grouping (1 1 10 6)
- "KJF" with the grouping (11 10 6)
Note that the grouping (1 11 06) is invalid because "06" cannot be mapped into 'F' since "6" is different from "06".
Given a string `s` containing only digits, return the number of ways to decode it.
The test cases are generated so that the answer fits in a 32-bit integer.
### Constraints
- `1 <= s.length <= 100`
- `s` contains only digits and may contain leading zero(s).
### Input Format
A single line containing the digit string `s`.
### Output Format
Print the number of ways to decode `s`.
Sample Cases
Example 1Sample Case
Input: 12
Output: 2
Example 2Sample Case
Input: 226
Output: 3
Example 3Sample Case
Input: 13
Output: 2
Example 4Sample Case
Input: 0
Output: 0
Constraints
Runtime Limit: 2000 ms per test batch
Memory Limit: 256 MB
Standard I/O stream reading
Official submissions are evaluated against hidden test cases on the server to verify time & memory complexity.