Driver code
public static void main ( String [ ] args ) { BinaryTree tree = new BinaryTree ( ) ; tree . root = new Node ( 5 ) ; tree . root . left = new Node ( 1 ) ; tree . root . right = new Node ( 6 ) ; tree . root . left . left = new Node ( 3 ) ; tree . root . right . left = new Node ( 7 ) ; tree . root . right . right = new Node ( 4 ) ; if ( tree . check ( tree . root ) == true ) System . out . println ( " YES " ) ; else System . out . println ( " NO " ) ; } }