heap-data-structure/d-ary-heap

/**
 * Sifts up a node.
 *
 * @param {int} arity arity of the heap
 * @param {function} compare the comparison function
 * @param {function} swap the swap function
 * @param {array} a the array where the heap is stored
 * @param {int} i is the root element
 * @param {int} j - 1 is the last leaf
 * @param {int} k is the target node
 */

export default function siftup(arity, compare, swap, a, i, j, k) {
    let current = k - i;

    // While we are not the root

    while (current !== 0) {
        // Address of the parent in a zero-based
        // d-ary heap

        const parent = i + Math.floor((current - 1) / arity);

        // If current value is greater than its parent
        // then we are done

        if (compare(a[i + current], a[parent]) >= 0) break;

        // Otherwise
        // swap with parent

        swap(a, i + current, parent);

        current = parent - i;
    }

    return i + current;
}