1656. Design an Ordered Stream

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`.

1656. Design an Ordered Stream
``````use std::collections::HashMap;
struct OrderedStream {
ptr: i32,
pairs: HashMap<i32, String>,
n: i32,
}

impl OrderedStream {
fn new(n: i32) -> Self {
let pairs = HashMap::new();
let ptr = 1;
OrderedStream { ptr, pairs, n }
}

fn insert(&mut self, id: i32, value: String) -> Vec<String> {
self.pairs.insert(id, value);
let mut res = vec![];
if self.ptr == id {
for i in id..=self.n {
if let Some(v) = self.pairs.get(&i) {
res.push(v.to_string());
self.ptr += 1;
} else {
break;
}
}
}
res
}
}

#[test]
fn test() {
let mut obj = OrderedStream::new(5);
assert_eq!(obj.insert(3, "ccccc".to_string()), vec_string![]);
assert_eq!(obj.insert(1, "aaaaa".to_string()), vec_string!["aaaaa"]);
assert_eq!(
obj.insert(2, "bbbbb".to_string()),
vec_string!["bbbbb", "ccccc"]
);
assert_eq!(obj.insert(5, "eeeee".to_string()), vec_string![]);
assert_eq!(
obj.insert(4, "ddddd".to_string()),
vec_string!["ddddd", "eeeee"]
);
}
``````