LC1656-Design-an-Ordered-Stream.py

"""
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.
"""
from typing import List

from run_tests import run_tests


class OrderedStream:

    def __init__(self, n: int):
        self.vals = [None, ] * n
        self.missing_id = 0
        self.n = n

    def insert(self, id: int, value: str) -> List[str]:
        self.vals[id - 1] = value
        if self.missing_id != id - 1:
            return []

        ans = list()
        while id <= self.n and self.vals[id - 1] is not None:
            ans.append(self.vals[id - 1])
            id += 1
        self.missing_id = id - 1
        return ans

# Your OrderedStream object will be instantiated and called as such:
# obj = OrderedStream(n)
# param_1 = obj.insert(id,value)
def test_code(instructions: List[str], values: List[str]):
    output = list()
    for instr, val in zip(instructions, values):
        if instr == "OrderedStream":
            obj = OrderedStream(*val)
            output.append(None)
        else:
            output.append(getattr(obj, instr)(*val))
    return output


if __name__ == "__main__":
    correct_answers = [
        [["OrderedStream", "insert", "insert", "insert", "insert", "insert"],
         [[5], [3, "ccccc"], [1, "aaaaa"], [2, "bbbbb"], [5, "eeeee"], [4, "ddddd"]],
         [None, [], ["aaaaa"], ["bbbbb", "ccccc"], [], ["ddddd", "eeeee"]]]
    ]
    print('Starting tests for ')
    run_tests(test_code, correct_answers)