4 / \ 3 5 / \ / \ 10 2 3 1
let root = newNode ( 4 ) ; root . left = newNode ( 3 ) ; root . right = newNode ( 5 ) ; root . right . left = newNode ( 3 ) ; root . right . right = newNode ( 1 ) ; root . left . left = newNode ( 10 ) ; root . left . right = newNode ( 2 ) ; printNodes ( root ) ;