                <a class="dropdown-item" href="../lectures/22-bsts-1/index.html">  22.  2/28 Binary Search Trees, Part I </a>
                
                  <a class="dropdown-item" href="../lectures/23-bsts-2/index.html">  23.  3/2 Binary Search Trees, Part II </a>
                
                  <a class="dropdown-item" href="../lectures/24-beyond-data-structures/index.html">  24.  3/4 Beyond Data Structures </a>
                
                  <a class="dropdown-item" href="../lectures/25-graph