ACODE  Alphacode
Alice and Bob need to send secret messages to each other and are discussing ways to encode their messages:
Alice: “Let’s just use a very simple code: We’ll assign ‘A’ the code word 1, ‘B’ will be 2, and so on down to ‘Z’ being assigned 26.”
Bob: “That’s a stupid code, Alice. Suppose I send you the word ‘BEAN’ encoded as 25114. You could decode that in many different ways!”
Alice: “Sure you could, but what words would you get? Other than ‘BEAN’, you’d get ‘BEAAD’, ‘YAAD’, ‘YAN’, ‘YKD’ and ‘BEKD’. I think you would be able to figure out the correct decoding. And why would you send me the word ‘BEAN’ anyway?”
Bob: “OK, maybe that’s a bad example, but I bet you that if you got a string of length 5000 there would be tons of different decodings and with that many you would find at least two different ones that would make sense.”
Alice: “How many different decodings?”
Bob: “Jillions!”
For some reason, Alice is still unconvinced by Bob’s argument, so she requires a program that will determine how many decodings there can be for a given string using her code.
Input
Input will consist of multiple input sets. Each set will consist of a single line of at most 5000 digits representing a valid encryption (for example, no line will begin with a 0). There will be no spaces between the digits. An input line of ‘0’ will terminate the input and should not be processed.
Output
For each input set, output the number of possible decodings for the input string. All answers will be within the range of a 64 bit signed integer.
Example
Input: 25114 1111111111 3333333333 0 Output: 6 89 1
hide comments
jaideeppyne:
20170619 08:12:04
can there be '0' in a valid input string ? The question says that character A has value 1....So '0' should not be there ? 

invinci:
20170619 01:31:32
Easy question in terms of dp, difficult in terms of cases:


sandeep_ipk:
20170611 12:01:28
Does anyone have an analytical explanation for the Fibonacci type solution?


nmongiya:
20170608 05:22:46
My code passed all the test cases mentioned in comments but I am getting 'Time limit exceeded' error. 

kartiks22:
20170607 22:11:07
for cases like :


ramesh_961:
20170607 11:32:41
@jasmeet


jasmeet:
20170602 08:23:27
can anyone explain how is 226210> 3? Last edit: 20170602 08:23:44 

kabramanan:
20170531 15:28:04
Here are some testcases if someone is still getting wrong answer(My solution is O(n)) :


sagnik_66:
20170519 17:47:16
Nice problem! 

slayerofcoding:
20170519 06:59:17
I get the runtime error SIGABRT. Any suggestion to overcome it.... 
Added by:  Adrian Kuegel 
Date:  20050709 
Time limit:  0.341s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All 
Resource:  ACM East Central North America Regional Programming Contest 2004 