#1656

Design an Ordered Stream

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array · hash table · design · data stream

Description

There is a stream of n (idKey, value) pairs arriving in an arbitrary order, where idKey is an integer between 1 and n and value is a string. No two pairs have the same id.

Design a stream that returns the values in increasing order of their IDs by returning a chunk (list) of values after each insertion. The concatenation of all the chunks should result in a list of the sorted values.

Implement the OrderedStream class:

- OrderedStream(int n) Constructs the stream to take n values.

- String[] insert(int idKey, String value) Inserts the pair (idKey, value) into the stream, then returns the largest possible chunk of currently inserted values that appear next in the order.

Example 1:

Input

["OrderedStream", "insert", "insert", "insert", "insert", "insert"]

[[5], [3, "ccccc"], [1, "aaaaa"], [2, "bbbbb"], [5, "eeeee"], [4, "ddddd"]]

Output

[null, [], ["aaaaa"], ["bbbbb", "ccccc"], [], ["ddddd", "eeeee"]]

Example 2:

Explanation

// Note that the values ordered by ID is ["aaaaa", "bbbbb", "ccccc", "ddddd", "eeeee"].

OrderedStream os = new OrderedStream(5);

os.insert(3, "ccccc"); // Inserts (3, "ccccc"), returns [].

os.insert(1, "aaaaa"); // Inserts (1, "aaaaa"), returns ["aaaaa"].

os.insert(2, "bbbbb"); // Inserts (2, "bbbbb"), returns ["bbbbb", "ccccc"].

os.insert(5, "eeeee"); // Inserts (5, "eeeee"), returns [].

os.insert(4, "ddddd"); // Inserts (4, "ddddd"), returns ["ddddd", "eeeee"].

// Concatentating all the chunks returned:

// [] + ["aaaaa"] + ["bbbbb", "ccccc"] + [] + ["ddddd", "eeeee"] = ["aaaaa", "bbbbb", "ccccc", "ddddd", "eeeee"]

// The resulting order is the same as the order above.

Solution