/**
 * Solve the knapsack problem.
 *
 * @param values Array of {[item, value, weight, maximum]} tuples for knapsack parameter.
 * @param capacity Capacity of knapsack.
 * @returns Tuple {[totalValue, items]} of selected items and total value of those items.
 */
export declare function knapsack<T>(values: [T, number, number, number?][], capacity: number): [number, [T, number][]];