1656. Design an Ordered Stream

There is a stream of n (id, value) pairs arriving in an arbitrary order, where id 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 id, String value) Inserts the pair (id, value) into the stream, then returns the largest possible chunk of currently inserted values that appear next in the order.

Example:

**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"]]

**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.

Constraints:

• 1 <= n <= 1000
• 1 <= id <= n
• value.length == 5
• value consists only of lowercase letters.
• Each call to insert will have a unique id.
• Exactly n calls will be made to insert.

# @lc code=start
using LeetCode

mutable struct OrderStream
    data::AbstractVector{T} where {T<:AbstractString}
    n::Int
    ptr::Int
    # initialize
    OrderStream(n::Int) = new(fill("", n), n, 1)
end

function insertdata!(stream::OrderStream, idkey::Int, val::String)
    stream.data[idkey] = val
    res = String[]
    isempty(stream.data[stream.ptr]) && return res
    for i in (stream.ptr):(stream.n)
        if isempty(stream.data[i])
            stream.ptr = i
            return res
        else
            push!(res, stream.data[i])
        end
    end
    return res
end

# @lc code=end

insertdata! (generic function with 1 method)

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