Data structure to store and retrieve a mapping between one action and multiple verbs in Java

What type of data structure must I use to build a dictionary like structure where one type of action is mapped to multiple verbs?

Example: Action1 will be mapped to verb1, verb2,verb5 and Action2 will be mapped to verb3,verb4.

Each action can have a varied number of verbs attached to it. The linking between action and Verbs will be hard coded.

Also, I need to search for a verb inputted by the user in the verb list defined and displayed in the corresponding action name:

Example: If the user input is verb 4 the system must return Action2

5 answers

  • answered 2018-05-16 05:38 sCom

    You can use a HashMap for this, the key would be the action and value would be the list of verbs:

     Map<String,List<String>> actionVerbMap=new HashMap<>();
    

  • answered 2018-05-16 05:43 Mạnh Quyết Nguyễn

    That sound like a Map of action and verb set

    Map<String, Set<String>>
    

    Use set to store verbs ensures the uniqueness and give good performance when you want to find action by given verb

  • answered 2018-05-16 06:20 Sweeper

    I think a HashMap<String, Action> will be suitable.

    Since you want to use the verbs to access the actions but not vice versa, the verbs should be the keys.

    Here are some example mappings:

    verb1 -> Action1
    verb2 -> Action1
    verb5 -> Action1
    verb3 -> Action2
    verb4 -> Action2
    

    This way you can ensure that no verb refers to two actions because keys are unique.

  • answered 2018-05-16 08:31 Rakesh Jha

    Data structure depends on relationship between verbs and actions. What is your relationship between verbs and action? 1-N N-N or N-1?

  • answered 2018-05-17 04:45 Dhaval Simaria

    If you want exact dictionary like data structure, go for Prefix Tree or Trie. If there are n Number of keys and m is the Length of the key then Trie has Time Complexity of O(m).

    Trie is preferrable if there is some lexicographical order or similar prefixes in your verbs.

                         t
                       /   \
                    te     ta
                   /  \      \
                 tea  ten    tar
    

    Leetcode: Prefix Tree

    Wikipedia: Trie

    If that is not the case then HashMap is suitable option as described in other answers.