comefrom: <awangdev>105. Construct Binary Tree from Preorder and Inorder Traversal_2.java
code: private Map<Integer, Integer> buildMap(int[] inorder) {
  
          Map<Integer, Integer> map = new HashMap<>();
          for (int i = 0; i < inorder.length; i++) map.put(inorder[i], i);
          return map;
      }
masked: private Map < Integer , Integer > var_0 ( int [ ] var_1 ) {
    Map < Integer , Integer > var_2 = new HashMap < > ( ) ;
    for ( int var_3 = 0 ;
    var_3 < var_1 . length ;
    var_3 ++ ) var_2 . put ( var_1 [ var_3 ] , var_3 ) ;
    return var_2 ;
  }
  