ode class="computeroutput"><a class="link" href="../boost/intrusive/sgtree.html" title="Class template sgtree">sgtree</a></code>. The first two
      are similar to <code class="computeroutput"><a class="link" href="../boost/intrusive/set.html" title="Class template set">set</a></code> or <code class="computeroutput"><a class="link" href="../boost/intrusive/multiset.html" title="Class template multiset">multiset</a></code> and the latter is a generalization
      that offers functions both to insert unique 