title: Bijective hash function
body: <p>The function that returns the hash can return the same index for different id values:</p>
  
  <pre><code>hash(id) = id%ARRAY_SIZE
  </code></pre>
  
  <p>Is there a way to have the hash function being bijective. I thought of:</p>
  
  <pre><code>hash(id) = id
  </code></pre>
  
  <p>But I do not have contiguous id values. Does someone have a better solution ? </p>