title: Postorder Inorder to Preorder conversion without constructing Binary Tree
body: <p>I have got given postorder and inorder. My task is to print preorder, but I can't construct a binary tree.</p>
  
  <p>Example:
  In: 
  POSTORDER
  4 2 7 5 9 8 6 3 1
  INORDER
  4 2 1 5 7 3 6 8 9</p>
  
  <p>Out:
  1 2 4 3 5 7 6 8 9 </p>
  
  <p>Can anyone help me how to solve this problem? </p>