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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).

Given a string ‘S’ containing only digits, return the number of ways to decode it.

```
Input: ‘S’ = "11106"
Output: 2
The possible ways are:-
(1 1 10 6),
(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".
```

Detailed explanation

```
1 <= T <= 10
1 <= | S | <= 100
Time Limit: 1 sec
```

```
2
12
226
```

```
2
3
```

```
For the first test case:-
"12" could be decoded as "AB" (1 2) or "L" (12).
For the second test case:-
"226" could be decoded as "BZ" (2 26), "VF" (22 6), or "BBF" (2 2 6).
```

```
2
1234
333
```

```
3
1
```