1656.DesignanOrderedStream.py

"""
    There are n (id, value) pairs, 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 takes the n pairs in an arbitrary order, and returns 
    the values over several calls in increasing order of their ids.

    Implement the OrderedStream class:
    - OrderedStream(int n) Constructs the stream to take n values and sets a 
      current ptr to 1.
    - String[] insert(int id, String value) Stores the new (id, value) pair in 
      the stream. After storing the pair:
        = If the stream has stored a pair with id = ptr, then find the longest 
          contiguous incrementing sequence of ids starting with id = ptr and 
          return a list of the values associated with those ids in order. 
          Then, update ptr to the last id + 1.
        = Otherwise, return an empty list.

    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
    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"].

    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.
"""
#Difficulty: Easy
#101 / 101 test cases passed.
#Runtime: 216 ms
#Memory Usage: 14.8 MB

#Runtime: 216 ms, faster than 100.00% of Python3 online submissions for Design an Ordered Stream.
#Memory Usage: 14.8 MB, less than 100.00% of Python3 online submissions for Design an Ordered Stream.

class OrderedStream:

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

    def insert(self, id: int, value: str) -> List[str]:
        result = []
        self.stream[id-1] = value
        if self.stream[self.index]:
            while self.index < self.n and self.stream[self.index]:
                result.append(self.stream[self.index])
                self.index += 1
        return result


# Your OrderedStream object will be instantiated and called as such:
# obj = OrderedStream(n)
# param_1 = obj.insert(id,value)