/** Count-Min Sketch with periodic aging (TinyLFU frequency estimator). */
export declare class CountMinSketch {
    #private;
    readonly depth: number;
    readonly width: number;
    private readonly rows;
    private adds;
    private readonly ageAfter;
    constructor(width?: number, depth?: number, ageAfter?: number);
    hit(key: string): number;
    estimate(key: string): number;
}
/**
 * Window-TinyLFU admission + LRU main cache (Caffeine-style).
 * Values live in the caller; this tracks keys, frequency and eviction order.
 */
export declare class WTinyLfu {
    #private;
    readonly capacity: number;
    readonly windowSize: number;
    readonly sketch: CountMinSketch;
    /** Optional access log for later cache-policy replay. */
    readonly trace: Array<{
        op: "hit" | "add" | "evict";
        key: string;
    }> | null;
    private readonly window;
    private readonly main;
    constructor(capacity: number, options?: {
        trace?: boolean;
        windowRatio?: number;
    });
    get size(): number;
    has(key: string): boolean;
    hit(key: string): void;
    /** Insert `key`. Returns a victim key when the cache is full. */
    add(key: string): string | undefined;
    delete(key: string): boolean;
    /** Evict the least valuable unpinned key. */
    evictExcept(pinned: ReadonlySet<string>): string | undefined;
}
export declare function wTinyLfu(capacity: number, options?: {
    trace?: boolean;
    windowRatio?: number;
}): WTinyLfu;
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