A counter normally increases, but process restarts reset it to zero. Treating the resulting negative delta as real traffic produces an incorrect rate.
Design a CounterRateCalculator class:
CounterRateCalculator() creates a stateless calculator.int totalIncrease(int[] values) returns the counter increase represented by the samples.double averageRate(int[] timestamps, int[] values) returns increase per time unit, rounded to 5 decimal places.
The first value is a baseline. For every later sample:
- If
current >= previous, add current - previous. - If
current < previous, assume a reset to zero occurred and add current.
For averageRate, divide the total increase by timestamps[last] - timestamps[0]. This exercise uses a simplified reset model and does not perform Prometheus boundary extrapolation.
Example 1:
Input:
Output:
Explanation: The increases are 30 and 30. Sixty events over twenty seconds gives 3 events per second.
Example 2:
Input:
Output:
Explanation: The decrease from 120 to 10 is a reset. The new counter has already recorded 10 events, so total increase is 30 + 10 + 30 = 70.
Constraints
2 <= values.length <= 10^50 <= values[i] <= 10^6- For
averageRate, timestamps.length == values.length. - Timestamps are strictly increasing non-negative integers.
- Total increase fits in a signed 32-bit integer.
- Round only the final average rate; answers are accepted within
10^-5. - At most
100 total method calls are made.
Calculate Counter Rates Across Resetsmedium