title: How to put postfix expressions in a binary tree?
body: <p>so i have a binary tree and a postfix expression "6 2 * 3 /"
  what is the algo to put it in a tree?
  like,</p>
  
  <pre><code>          [/]
            / \
          [*]  [3]
          / \
        [6] [2]
  </code></pre>