docs: public int binarySearchFromTo(long key, int from, int to) {
  	int low=from;
  	int high=to;
  	while (low <= high) {
  		int mid =(low + high)/2;
  		long midVal = get(mid);
  
  		if (midVal < key) low = mid + 1;
  		else if (midVal > key) high = mid - 1;
  		else return mid; // key found
  	}
  	return -(low + 1);  // key not found.
  }