I was practicing the dynamic programming problem on SPOJ. But I have no idea how to solve this one.
Can anyone please help ME in solving http://www.spoj.pl/problems/ACODE/ problem on SPOJ
Thanks!
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
Starting from the left, do the following:
If you still can’t get it, you can take a look at the Welcome to Code Jam problem. It somewhat similar and has readily available explanations for it.