private static int linearSearch(int[] a, int low, int high, int key) {
        assert low < high;
        while (low < high && a[low] <= key) {
            ++low;
        }
        return low;
    }
Modified binary search:
 - Returns the first index where a[index] is larger then key
predicate-search/src/main/java/com/yahoo/search/predicate/utils/PostingListSearch.java