/**
 * MaxDiff (Best-Worst Scaling) utility module.
 *
 * Provides balanced incomplete block design (BIBD) generation for MaxDiff trials,
 * utility score computation, and top-N filtering with tie handling.
 */
export interface MaxDiffTrial {
    trialIndex: number;
    itemValues: string[];
}
export interface MaxDiffTrialAnswer {
    trialIndex: number;
    itemValues: string[];
    bestValue: string;
    worstValue: string;
}
/**
 * Generate a balanced incomplete block design for MaxDiff trials.
 *
 * Guarantees:
 * - Every item appears in at least one trial (Req 5.1)
 * - Each item appears approximately equally — difference of at most 1 (Req 14.1)
 * - Pair co-appearances bounded by ceil(T*K*(K-1) / (S*(S-1))) + 1 (Req 14.2)
 * - At least ceil(3*S/K) trials for statistical adequacy (Req 5.5)
 *
 * @param itemValues Array of surviving item value strings (S items, 3 ≤ S ≤ 7)
 * @param itemsPerTrial Number of items per trial (K, 3 ≤ K ≤ 5)
 * @returns Array of MaxDiffTrial objects
 */
export declare function generateMaxDiffDesign(itemValues: string[], itemsPerTrial: number): MaxDiffTrial[];
/**
 * Compute utility scores from completed MaxDiff trial answers.
 *
 * Formula: (best_count - worst_count) / total_appearances
 * Normalized to 0–100 scale.
 *
 * @param trials Array of completed trial answers
 * @returns Map of item value → utility score (0–100)
 */
export declare function computeUtilityScores(trials: MaxDiffTrialAnswer[]): Map<string, number>;
/**
 * Filter to retain the top N items by descending utility score.
 * If items are tied at the boundary, all tied items are included
 * (potentially exceeding N).
 *
 * @param utilities Map of item value → utility score
 * @param topN Number of top items to retain
 * @returns Array of item values that made the cut
 */
export declare function filterTopN(utilities: Map<string, number>, topN: number): string[];