![]() The items are temporally ordered (newest first), items only reference older items, they never reference a more recent item. #> pmap(list(tree_list, cut_lookup), cut_tree)Īs discussed here the items can merge. └─rlang::abort(message, class = c(class, "vctrs_error"). │ └─purrr::pmap(list(tree_list, cut_lookup), cut_tree) ![]() ├─global cut_trees(tree_list, cut_lookup) # function to apply cuts to a list of trees I tried the following, but I get errors: # function to cut branches from a single treeįilter(!id_from %in% nodes_to_cut_table) %>% Now I am trying to do the opposite, i.e., cut branches of document trees according to a lookup list by using a function. This generic version is far more reusable, as it is type-parameterised: it can objects of any type, not just Strings.I just learned how to add branches to linked documents (document trees). If you wanted to type-parameterise your Node class, instead of having LinkedStack then implements Stack (or, if using generics: LinkedStack implements Stack), and should have a private member variable of type Node (or Node), representing the top of the stack (thus you could call it top). Returns the element on the top of the stack Doing this will help you better understand Stack's methods, and why they should have the return types they do. If you haven't covered generics yet, though, don't worry about using type parameters.) For bonus points, list the pre- and post-conditions, return types (and, if you're comfortable with them, exceptions) for each of the interface methods. (As Campbell suggested, you should make these generic types: e.g. How about defining an interface for a Stack, and having another class, LinkedStack, that implements that interface? That way you can code against an interface rather than an implementation. There's actually no need to have separate class just to kick off the program, in my opinion: Stick the main method in your ReversePolish class. I have a few suggestions, but the most important point is the one Stephan has already made: you do not want to iterate the stack.įirstly, unless you have been explicitly told to name it as such, "Program1" is a terrible name for a class. Public class ReversePolish extends StackLL Coding example for the question Im confused on how id go about overloading the operator on a stack using a linked list-C . Result = printNode.toString() "\n" //.toString() belongs to Node class We verify if the first half and second half are equivalent by comparing node by node. Then we reverse the second half of the linked list. Find the middlemost element of the linked list. There are four operations needed to be formed to implement our algorithm. ![]() Once again thanks for taking the time to read this and help.įor(int i = 0 i |data2|ref3|-!>|data3|ref4|-!>|data4|null| In this algorithm, we simply reverse half of the linked list. the iterateStack() method in the ReversePolish class is suppose to go through the stack to look for operands and operators and perform the necessary operations ( at least i think that's how i need to do it). When testing my stackCount() method in the ReversePolish class the method is reading the count as zero BUT the count method works perfectly when calling it from the stack (i hope that made sense). I am stuck on how to iterate through the stack to check for operands. With the stack we have to create a Reverse Polish Notation calculator ( , -, *, / only). ![]() ![]() We have to create our own stack data structure using a linked list (can't use Java's linked list either). I have an assignment that I need some help with. ![]()
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