text: Input tree
code: let root = new Node ( 1 ) ; root . left = new Node ( 2 ) ; root . right = new Node ( 3 ) ; root . left . left = new Node ( 4 ) ; root . left . right = new Node ( 5 ) ; root . right . left = new Node ( 6 ) ; root . right . right = new Node ( 7 ) ; root . left . left . left = new Node ( 8 ) ; root . left . left . right = new Node ( 9 ) ; let target = 3 ; let p = sumofsubtree ( root ) ;