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by Sumit Chourasia | Nov 16, 2020 | Category :coding | Tags : algorithm array data-structure easy leetcode

Design an Ordered Stream - Array - Easy - LeetCode

Design an Ordered Stream - Array - Easy - LeetCode

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.

 

public class OrderedStream {
    string[] strArr;
    int ptr = 0;
    public OrderedStream(int n) {
        strArr = new string[n];
    }
    
    public IList<string> Insert(int id, string value) {
        id = id-1;
        strArr[id]=value;
        var result = new List<string>();
        if(ptr==id){
            while(ptr < strArr.Length && strArr[ptr]!=null){
                result.Add(strArr[ptr]);
                ptr++;
            }
        }
        
        return result;
    }
}

/**
 * Your OrderedStream object will be instantiated and called as such:
 * OrderedStream obj = new OrderedStream(n);
 * IList<string> param_1 = obj.Insert(id,value);
 */

Time Complexity: O(n)

Space Complexity: O(n)

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