Method partition

java/0347-top-k-frequent-elements.java:67–84

(
        int[] keys,
        Map<Integer, Integer> map,
        int left,
        int right,
        int pivot
    )

    }

    private int partition(
        int[] keys,
        Map<Integer, Integer> map,
        int left,
        int right,
        int pivot
    ) {
        int pivotValue = map.get(keys[pivot]);
        swap(keys, pivot, right);
        int index = left;

        for (int i = left; i <= right; i++) if (map.get(keys[i]) < pivotValue) {
            swap(keys, i, index);
            index++;
        }
        swap(keys, right, index);
        return index;
    }

    private void swap(int[] array, int i1, int i2) {
        int temp = array[i1];