pan class="hljs-keyword">var</span>
      d = initDeque[<span class="hljs-built_in">int</span>]()
      p = initIntSet() <span class="hljs-comment">## p stands for packedsets, I tried to use it but I do not have it yet</span>
      <span class="hljs-comment">## d and p are synchronized to contain same stuff</span>
      n: <span class="hljs-built_in">int</span>
    <span class="hljs-keyword">for</span> i <span class="hljs-keyword">in</span> <span class="hljs-number">0</span> ..&lt; l:
      d.addLast(s[i])
