#2526

Find Consecutive Integers from a Data Stream

medium · 50.8% accepted · 339 likes · top 39%

hash table · design · queue · counting · data stream

⊣ practice⊣ open on leetcode ↗

Description

For a stream of integers, implement a data structure that checks if the last k integers parsed in the stream are equal to value.

Implement the DataStream class:

 - DataStream(int value, int k) Initializes the object with an empty integer stream and the two integers value and k.

 - boolean consec(int num) Adds num to the stream of integers. Returns true if the last k integers are equal to value, and false otherwise. If there are less than k integers, the condition does not hold true, so returns false.

Example 1:

Input
["DataStream", "consec", "consec", "consec", "consec"]
[[4, 3], [4], [4], [4], [3]]
Output
[null, false, false, true, false]

Example 2:

Explanation
DataStream dataStream = new DataStream(4, 3); //value = 4, k = 3
dataStream.consec(4); // Only 1 integer is parsed, so returns False.
dataStream.consec(4); // Only 2 integers are parsed.
// Since 2 is less than k, returns False.
dataStream.consec(4); // The 3 integers parsed are all equal to value, so returns True.
dataStream.consec(3); // The last k integers parsed in the stream are [4,4,3].
// Since 3 is not equal to value, it returns False.

Solution