export type EditOp<T> = {
    type: 'equal';
    a: T;
    b: T;
} | {
    type: 'replace';
    a: T;
    b: T;
} | {
    type: 'insert';
    b: T;
} | {
    type: 'delete';
    a: T;
};
export interface LevenshteinOptions<T> {
    equal: (a: T, b: T) => boolean;
    substitutionCost?: (a: T, b: T) => number;
    insertCost?: number;
    deleteCost?: number;
}
/**
 * Weighted Levenshtein edit distance (Needleman-Wunsch), computed via O(n*m)
 * dynamic programming and backtracked into the cheapest sequence of
 * equal/insert/delete/replace edits. Unlike a plain LCS diff, this allows two
 * non-equal items to be paired up as a single "replace" rather than always
 * splitting into an unrelated delete + insert.
 */
export declare function levenshteinDiff<T>(a: T[], b: T[], options: LevenshteinOptions<T>): EditOp<T>[];