title: remove elements from link list whose sum equals to zero
body: <p>Given a list in form of linked list,  I have to canceled out all the resources whose sum up to 0(Zero) and return the remaining list.</p>
  
  <p>Like </p>
  
  <pre><code>6 -6 3 2 -5 4 returns 4
  8 10 4 -1 -3 return 8 10
  </code></pre>
  
  <p>I only need algorithm to solve this question. </p>