Method partition

src/main/java/com/thealgorithms/others/BFPRT.java:113–127

Partitions the array around a pivot. @param arr the input array @param begin the starting index @param end the ending index @param num the pivot element @return the range where the pivot is located

(int[] arr, int begin, int end, int num)

     * @return the range where the pivot is located
     */
    public static int[] partition(int[] arr, int begin, int end, int num) {
        int small = begin - 1;
        int cur = begin;
        int big = end + 1;
        while (cur != big) {
            if (arr[cur] < num) {
                swap(arr, ++small, cur++);
            } else if (arr[cur] > num) {
                swap(arr, --big, cur);
            } else {
                cur++;
            }
        }
        return new int[] {small + 1, big - 1};
    }

    /**
     * Finds the median of the elements between the specified range.