Good method to compute product of the most common integers in a list?
<p>Let's say I have an array of n integers and I am supposed to return
the product of most common integers.</p>

<p>Example: (2,3,4,2,2,1,4)- returns 8.</p>

<p>I can use normal arrays to store the values. </p>

<p>If I want to have runtime optimization, should I use hashtable in C# or dictionary?
Will that help me have space optimization as well? 
Or is there any other approach to have space optimization?</p>
