// Array of tree nodes
// Determine if the array is a binary tree

       A
      / \
     B   C
    / \   \
   D   E   F

TreeNode f = new TreeNode (null, null);
TreeNode  d= new TreeNode (null, null);
TreeNode e = new TreeNode (null, null);
TreeNode b = new TreeNode (d, e);
TreeNode c = new TreeNode (null, f);
TreeNode a = new TreeNode (b, c);

new Array[b, d, f, a, c, e]

class TreeNode {
    TreeNode* left;
    TreeNode* right;
    int value;
}