5
          /
        4       6
      /       /
     3    x   x   7
    /   /  /   /
   x  x x x x x  x  8


[5, 4, 6, 3, null, null, 7, null, null, null, null, null, null, null, 8]

5
          /
        4       6
      /       /
     3    x   x   x
    /
   2  x

[5, 4, 6, 3, null, null, null, 2, null]