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Problem Brief

Perform Queries

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Amazon ships millions of packages every day. A large percentage of them are fulfilled by Amazon, so it is important to minimize shipping costs. It has been found that moving a group of 3 packages to the shipping facility together is most efficient. The shipping process needs to be optimized at a new warehouse. There are the following types of queries or requests:

  • INSERT package id: insert package id in the queue of packages to be shipped
  • SHIP -: ship the group of 3 items that were in the queue earliest i.e. they are returned in the order they entered

    • Perform q queries and return a list of lists, one for every SHIP - type query. The lists are either; 3 package ID strings in the order they were queued. Or, if there are not enough packages in the queue to fulfill the query, the result is I"N/A"J.

    Note:

  • Initially, the queue is empty.
  • The list of packages shipped per group should be in the order they were queued. The function performQueries take

    List<List<>>

    of type String as a parameter which contains each query where - 🦆

    • --> list.get(i).get(0) = INSERT | SHIP

    --> list.get(i).get(1) = shipmentID | -

    Returns

    List>: a list of lists, one for every SHIP - type query

    1Example 1

    Input
    queries = [["INSERT", "GT23513413"], ["INSERT", "TQC2451340"], ["SHIP", "-"], ["INSERT", "VYP8561991"], ["SHIP", "-"]]
    Output
    [["N/ A"], ["GT23513413", "TQC2451340", "VYP8561991"]]
    Explanation
    :)
    public String[][] performQueries(String[][]queries) {
  // write your code here
}
    Input

    queries

    [["INSERT", "GT23513413"], ["INSERT", "TQC2451340"], ["SHIP", "-"], ["INSERT", "VYP8561991"], ["SHIP", "-"]]

    Output

    [["N/ A", "GT23513413", "TQC2451340", "VYP8561991"]]

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