Question

1656. Design an Ordered Stream

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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:

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.

Solutions

Solution 1

class OrderedStream:
  def __init__(self, n: int):
    self.data = [None] * n
    self.ptr = 0

  def insert(self, idKey: int, value: str) -> List[str]:
    self.data[idKey - 1] = value
    ans = []
    while self.ptr < len(self.data) and self.data[self.ptr]:
      ans.append(self.data[self.ptr])
      self.ptr += 1
    return ans


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

class OrderedStream {
  private String[] data;
  private int ptr;

  public OrderedStream(int n) {
    data = new String[n];
    ptr = 0;
  }

  public List<String> insert(int idKey, String value) {
    data[idKey - 1] = value;
    List<String> ans = new ArrayList<>();
    while (ptr < data.length && data[ptr] != null) {
      ans.add(data[ptr++]);
    }
    return ans;
  }
}

/**
 * Your OrderedStream object will be instantiated and called as such:
 * OrderedStream obj = new OrderedStream(n);
 * List<String> param_1 = obj.insert(idKey,value);
 */

class OrderedStream {
public:
  vector<string> data;
  int ptr = 0;

  OrderedStream(int n) {
    data.resize(n, "");
  }

  vector<string> insert(int idKey, string value) {
    data[idKey - 1] = value;
    vector<string> ans;
    while (ptr < data.size() && data[ptr] != "") ans.push_back(data[ptr++]);
    return ans;
  }
};

/**
 * Your OrderedStream object will be instantiated and called as such:
 * OrderedStream* obj = new OrderedStream(n);
 * vector<string> param_1 = obj->insert(idKey,value);
 */

type OrderedStream struct {
  data []string
  ptr  int
}

func Constructor(n int) OrderedStream {
  data := make([]string, n)
  return OrderedStream{data, 0}
}

func (this *OrderedStream) Insert(idKey int, value string) []string {
  this.data[idKey-1] = value
  var ans []string
  for this.ptr < len(this.data) && this.data[this.ptr] != "" {
    ans = append(ans, this.data[this.ptr])
    this.ptr++
  }
  return ans
}

/**
 * Your OrderedStream object will be instantiated and called as such:
 * obj := Constructor(n);
 * param_1 := obj.Insert(idKey,value);
 */

class OrderedStream {
  private ptr: number;
  private vals: string[];

  constructor(n: number) {
    this.ptr = 0;
    this.vals = new Array(n);
  }

  insert(idKey: number, value: string): string[] {
    this.vals[idKey - 1] = value;
    const res = [];
    while (this.vals[this.ptr] != null) {
      res.push(this.vals[this.ptr]);
      this.ptr++;
    }
    return res;
  }
}

/**
 * Your OrderedStream object will be instantiated and called as such:
 * var obj = new OrderedStream(n)
 * var param_1 = obj.insert(idKey,value)
 */

struct OrderedStream {
  ptr: usize,
  vals: Vec<Option<String>>,
}

/**
 * `&self` means the method takes an immutable reference.
 * If you need a mutable reference, change it to `&mut self` instead.
 */
impl OrderedStream {
  fn new(n: i32) -> Self {
    Self { ptr: 0, vals: vec![None; n as usize] }
  }

  fn insert(&mut self, id_key: i32, value: String) -> Vec<String> {
    self.vals[(id_key - 1) as usize] = Some(value);
    let mut res = Vec::new();
    while self.ptr < self.vals.len() {
      if let Some(s) = &self.vals[self.ptr] {
        res.push(s.clone());
        self.ptr += 1;
      } else {
        break;
      }
    }
    res
  }
}/**
 * Your OrderedStream object will be instantiated and called as such:
 * let obj = OrderedStream::new(n);
 * let ret_1: Vec<String> = obj.insert(idKey, value);
 */