* Traversing an array should never be used for searching;
   * Using a hash is a pretty smart solution, except:
     - It has memory implication (hence not always can be used);
     - It slows down considerably for huge arrays (or,  at least you have to build your own hash structure with some pretty hashing function);
     - In any case, questions arise: is it smart to build it every time one needs a lookup? What if the contents of an array change all the time?.., etc.
	
   * There are other algorithms in CS.