/**
 *  The `ThreeSumFast` class provides static methods for counting
 *  and printing the number of triples in an array of distinct integers that
 *  sum to 0 (ignoring integer overflow).
 *  <p>
 *  This implementation uses sorting and binary search and takes time
 *  proportional to n^2 log n, where n is the number of integers.
 *  <p>
 *  For additional documentation, see <a href="https://algs4.cs.princeton.edu/14analysis">Section 1.4</a> of
 *  <i>Algorithms, 4th Edition</i> by Robert Sedgewick and Kevin Wayne.
 */
export default class ThreeSumFast {
    static count(a: number[], sum?: number): number;
    private static containsDuplicates;
}