LeetCode-in-Java

2526. Find Consecutive Integers from a Data Stream

Medium

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]

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.

Constraints:

• 1 <= value, num <= 109
• 1 <= k <= 105
• At most 105 calls will be made to consec.

Solution

public class DataStream {
    private final int value;
    private final int k;
    private int count;

    public DataStream(int value, int k) {
        this.value = value;
        this.k = k;
    }

    public boolean consec(int num) {
        count = num == value ? count + 1 : 0;
        return count >= k;
    }
}

/*
 * Your DataStream object will be instantiated and called as such:
 * DataStream obj = new DataStream(value, k);
 * boolean param_1 = obj.consec(num);
 */

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