Decode Ways
MediumP2Coding
A message of letters is encoded with A -> 1, B -> 2, ..., Z -> 26 and the codes are written one after another with no separators. Given the digit string s, return the number of different ways to decode it back into letters.
A code never has a leading zero, so "06" is not a valid code and "0" alone cannot be decoded. If s cannot be decoded at all, return 0.
Example 1
- Input
- s = "12"
- Output
- 2
- Why
- "AB" (1 2) or "L" (12).
Example 2
- Input
- s = "226"
- Output
- 3
- Why
- "BZ" (2 26), "VF" (22 6) or "BBF" (2 2 6).
Example 3
- Input
- s = "06"
- Output
- 0
Constraints
- 1 <= s.length <= 60
scontains only digits.- The answer fits in a 53-bit integer.
Hints
Give it a real attempt first. Run shows which examples fail.
Saved automatically
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