recursion

问题 How can I convert this recursive function to an iterative function? #include <cmath> int M(int H, int T){ if (H == 0) return T; if (H + 1 >= T) return pow(2, T) - 1; return M(H - 1, T - 1) + M(H, T - 1) + 1; } Well it's a 3-line code but it's very hard for me to convert this to an iterative function. Because it has 2 variables. And I don't know anything about Stacks so I couldn't convert that. My purpose for doing this is speed of the function. This function is too slow. I wanted to use map

问题 I have a model like so.... class Person(models.Model): name = models.CharField(max_length=55,null=False, blank=False) parent = models.ForeignKey('Person.Person', null=False, blank=False) I want to create a recursive function that will eventually return a dictionary of an entire persons family tree.... So for example... first_person = Person.objects.filter(name='FirstPerson') family_tree = GetChildren(first_person) Where GetChildren is my recursive function that will continuously call

问题 I would like to visualize some deeply nested data using networkD3 . I can't figure out how to get the data into the right format before sending to radialNetwork . Here is some sample data: level <- c(1, 2, 3, 4, 4, 3, 4, 4, 1, 2, 3) value <- letters[1:11] where level indicates the level of the nest, and value is the name of the node. By using these two vectors, I need to get the data into the following format: my_list <- list( name = "root", children = list( list( name = value[1], ## a

问题 Today morning I answered a question which is related to StackoverflowException . The person has asked when Stackoverflow exception occurs See this link Simplest ways to cause stack overflow in C#, C++ and Java So my question is that is there any method by which we can compute the method call stacks size dynamically in our program and then applying a check before calling a method which checks whether method call stack has space to accommodate it or not to prevent StackOverflowException. As I

问题 I am working with a JSON object which can have a property ids at any leaf. I want to traverse the object and find all of the instances of the ids property and store each id in a collection. Mocked up JSON Object (the ids property could be at much deeper property locations). { "id": "b38a683d-3fb6-408f-9ef6-f4b853ed1193", "foo": { "ids": [ { "id": "bd0bf3bd-d6b9-4706-bfcb-9c867e47b881" }, { "id": "d1cc529d-d5d2-4460-b2bb-acf24a7c5999" }, { "id": "b68d0c8c-548e-472f-9b01-f25d4b199a71" } ], "baz

问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 4 years ago . I have a tree of directories, sub-directories, and files (in some but not all the directories). Here's an example of the whole tree: /food /food/drinks /food/drinks/water.html /food/drinks/milk.html /food/drinks/soda.html /food/entrees /food/entrees/hot /food/entrees/hot/hamburger

问题 Given a list of arbitrairly deep nested lists of arbitrary size, I would like an flat, depth-first iterator over all elements in the tree, but with path indicies as well such that: for x, y in flatten(L), x == L[y[0]][y[1]]...[y[-1]]. That is L = [[[1, 2, 3], [4, 5]], [6], [7,[8,9]], 10] flatten(L) should yield: (1, (0, 0, 0)), (2, (0, 0, 1)), (3, (0, 0, 2)), (4, (0, 1, 0)), (5, (0, 1, 1)), (6, (1, 0)), (7, (2, 0)), (8, (2, 1, 0)), (9, (2, 1, 1)), (10, (3,)) I made a recursive implementation

问题 Given a list of arbitrairly deep nested lists of arbitrary size, I would like an flat, depth-first iterator over all elements in the tree, but with path indicies as well such that: for x, y in flatten(L), x == L[y[0]][y[1]]...[y[-1]]. That is L = [[[1, 2, 3], [4, 5]], [6], [7,[8,9]], 10] flatten(L) should yield: (1, (0, 0, 0)), (2, (0, 0, 1)), (3, (0, 0, 2)), (4, (0, 1, 0)), (5, (0, 1, 1)), (6, (1, 0)), (7, (2, 0)), (8, (2, 1, 0)), (9, (2, 1, 1)), (10, (3,)) I made a recursive implementation

问题 I've read and searched and I'm yet to figure out an answer to this relatively simple issue. I have a class: public class AccessibleTreeItem { public string name; public List<AccessibleTreeItem> children; public AccessibleTreeItem() { children = new List<AccessibleTreeItem>(); } } which is populate using a series of functions that don't really matter in this context, but what I'm looking for is a way to search through ALL of the children items in the list, searching for a particular 'name'

问题 I've read and searched and I'm yet to figure out an answer to this relatively simple issue. I have a class: public class AccessibleTreeItem { public string name; public List<AccessibleTreeItem> children; public AccessibleTreeItem() { children = new List<AccessibleTreeItem>(); } } which is populate using a series of functions that don't really matter in this context, but what I'm looking for is a way to search through ALL of the children items in the list, searching for a particular 'name'