We have a message for you. But we hid it. Unless you know the secret phrase, it will remain hidden.
Can you write the algorithm to find it?
Here is a couple of important hints to help you out:
- An anagram of the phrase is: "poultry outwits ants"
- There are three levels of difficulty to try your skills with
- The MD5 hash of the easiest secret phrase is "e4820b45d2277f3844eac66c903e84be"
- The MD5 hash of the more difficult secret phrase is "23170acc097c24edb98fc5488ab033fe"
- The MD5 hash of the hard secret phrase is "665e5bcb0c20062fe8abaaf4628bb154"
| MD5 Hashed Text | Phrase |
|---|---|
| e4820b45d2277f3844eac66c903e84be | printout stout yawls |
| 23170acc097c24edb98fc5488ab033fe | ty outlaws printouts |
| 665e5bcb0c20062fe8abaaf4628bb154 | wu lisp not statutory |
The most intuitive to solve this problem is to find all the anagrams of the hint text. However, it's gonna be N! possibilities where N is the length of hint text, which makes it barely feasible to implement. Therefore, My first priority is to reduce the amount of possibl 562E e anagrams.
- Loop through the wordlist and filter out all invalid words ( a valid word should be a subset of the hint text)
- Combine words from wordlist to see if it's an anagram of the hint text, I've implemented in both iteration and recursion
- Recusion: recursively add word to sentence, and check if any character count of the sentence exceed that of hint text (stops) or is an anagram of hint text.
- Iteration: A fix number of loops are implemented, in this case 4. That is to say it can only find all anagrams containing maximum 4 words.
- Save the anagrams so that it can be reused
- Loop through and MD5 hash the anagrams, and check if it euqals to target hashed code
This a maven project using springboot framework.
Requirements:
- Maven 3.8.1
- Java 11
Three ways of running it
-
Please run RabbitChallengeApplication directly in IDE
-
# Package via maven mvn package # Execute the jar file