title: comparing vectors in a large data set
body: <p>I have a two dimensional vector of integer type that contains a large amount of vectors ( i.e <code>18000</code> and above ), and there is a considerable amount amount of repetitive vectors in this pool. What I want to do is to detect the similar vectors and delete one of them. 
  What I am currently doing is that I am comparing each vector against the entire pool using the following function :`</p>
  
  <pre><code>bool compareVectors(vector&lt;int&gt; a, vector&lt;int&gt; b)
  {
      if (a.size() != b.size())
      {
          return false;
      }
      sort(a.begin(), a.end());
      sort(b.begin(), b.end());
      return (a == b);
  }
  </code></pre>
  
  <p>But this doesn't efficiently do the process presumably due to the large amounts of comparisons I am making. Is there any possible efficient ways to do this ?</p>