/**
 * Sliding time window data structures for metric computation.
 *
 * Both windows use a chronologically-ordered deque and binary search for
 * pruning, keeping amortized cost O(log n) per event rather than O(n).
 *
 * @module alerting/sliding-window
 */
/** Tracks event counts for rate computation (e.g., failure_rate). */
export declare class CounterWindow {
    #private;
    constructor(windowMs: number);
    /** Record an event with its timestamp and failure status. */
    record(timestamp: number, failed: boolean): void;
    /** Returns failure rate as a number between 0 and 1. Returns 0 if no events. */
    rate(now: number): number;
}
/** Stores individual values for percentile computation (e.g., p99 duration). */
export declare class HistogramWindow {
    #private;
    constructor(windowMs: number);
    /** Record an observation with its timestamp. */
    record(timestamp: number, value: number): void;
    /** Returns the p-th percentile value (p between 0 and 100). Returns 0 if no observations. */
    percentile(p: number, now: number): number;
}