public int firstOccur(int[] arr, int k) {
if (arr == null || arr.length combinedOccur(int[] arr, int k) {
BinarySearchOccurences obj = new BinarySearchOccurences();
int startIndex = obj.firstOccur(arr, k);
int endIndex = obj.lastOccur(arr, k);
if (startIndex == -1 || endIndex == -1) {
throw new IllegalArgumentException("k does not exist in array");
}
ArrayList result = new ArrayList();
result.add(startIndex);
result.add(endIndex);
return result;
}