      The default implementation uses a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special">&lt;&gt;</span></code> or a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">set</span><span class="special">&lt;&gt;</span></code> with a complexity of:
          </p>
<div class="blockquote"><blockquote class="blockquote"><p>
              O(log n