1058. Streak Watcher
A factory sensor reports one integer reading per second, and an alarm must fire whenever the machine has shown the same fault code value for k consecutive readings. Readings arrive one by one and old readings are not stored by the caller.
Implement StreakWatcher. The constructor receives the fault code value and the streak length k. Each call consec(num) records a new reading num and returns true when the most recent k readings are all equal to value; it returns false if fewer than k readings exist or any of them differs. Each call must take O(1) time and O(1) extra space.
Example 1
- Input:
- operations = ["StreakWatcher","consec","consec","consec","consec","consec"]arguments = [[7,3],[7],[7],[7],[4],[7]]
- Output:
- [null,false,false,true,false,false]
- Explanation:
Only the third call sees three 7s in a row; the 4 breaks the streak and the final 7 starts it afresh.
Example 2
- Input:
- operations = ["StreakWatcher","consec","consec","consec","consec"]arguments = [[0,1],[5],[0],[0],[2]]
- Output:
- [null,false,true,true,false]
- Explanation:
With k = 1 the answer only depends on whether the newest number equals 0.
Example 3
- Input:
- operations = ["StreakWatcher","consec","consec","consec","consec","consec"]arguments = [[9,2],[9],[1],[9],[9],[9]]
- Output:
- [null,false,false,false,true,true]
- Explanation:
The window of two newest numbers is all 9s from the fourth call onwards.
Constraints
1 ≤ k ≤ 105
0 ≤ value, num ≤ 109
At most 104 calls to consec
How this problem is judged
- Answers
- Your answer must match exactly. Numbers compare by value, so 2 and 2.0 are equal.
- Input
- Each case is an operation log.
operationsnames the class first and then each method call;argumentsholds the arguments for each, in the same order. Your answer is one list with a result per operation -nullfor the constructor and for methods that return nothing. - Time per case
- Python 2,000 msC++ 500 msJava 1,000 msJavaScript 1,000 msTypeScript 1,000 ms
Expected complexity
- Time
- O(1) per call
- Space
- O(1)