Description
A message containing letters from A-Z can be encoded into numbers using the mapping: 'A' -> "1", 'B' -> "2", ..., 'Z' -> "26". Given a string s containing only digits, return the number of ways to decode it.
Examples
Input:
s = "12"Output:
2Explanation:
"12" could be decoded as "AB" (1 2) or "L" (12).
Input:
s = "226"Output:
3Explanation:
"226" could be decoded as "BZ" (2 26), "VF" (22 6), or "BBF" (2 2 6).
Input:
s = "06"Output:
0Explanation:
"06" cannot be mapped (leading zero).
Constraints
- •
1 ≤ s.length ≤ 100 - •
s contains only digits and may contain leading zero(s).