recursion

问题 I have an directory tree which has been passed to array. I would like to there empty folders inside this array. How can I determine empty folders like /wp-content/uploads/2014/02/ and /wp-content/uploads/2014/ . How can I delete them recursively. Here is my array array ( 0 => './do-update.php', 5 => './wp-config.php', 6 => './wp-content/', 7 => './wp-content/uploads/', 8 => './wp-content/uploads/2013/', 9 => './wp-content/uploads/2013/05/', 10 => './wp-content/uploads/2013/05/kabeduvarkad

问题 I have the following recursive query which would run in 11g but is not supported in Oracle 10g database: with st as ( select rownum id, case when rownum-1 < 1 then null else rownum-1 end parent_id, customer, tickets from tickets ), st2(id, parent_id, customer, tickets, offset) as ( select id, parent_id, shuffler_id, subno, contrno, tickets, 0 offset from st where id = 1 union all select st2.id, st2.parent_id, st2.tickets, (st.tickets + st.offset) offset from st, st2 where st2.parent_id = st

问题 I am learning Java from a book, and come across a chapter regarding recursion using a factorial example. //A simple example of recursion package tutorials; class Factorial { // this is a recursive method int fact (int n) { int result; if(n==1) return 1; result = fact(n - 1) * n; return result; } } class Recursion { public static void main(String args[]) { Factorial f = new Factorial(); System.out.println("Factorial of 3 is " + f.fact(3)); System.out.println("Factorial of 4 is " + f.fact(4));

问题 What is the time complexity of the recurrence T(n) = 2T(n-1) + 4 ? I'm having serious problems with this. I tried: T(n) = 2T(n-1)+4 = 2(2T(n-2)+4)+4 = 4T(n-2)+12= 4(2T(n-3)+4)+4 = 8T(n-3)+20 = 8(2T(n-4)+4)+4 = 16T(n-4)+36 =… T(n) = 2^kT(n-k) + (4+2^(k+1)) so it looks like T(n) = 2^n + (4+2^(n+1)) but it doesn't seem right... please help :( 回答1: Your computation are wrong. I'm assuming here that T(0)=0 T(n) = 2T(n-1)+ 4 = 2(2T(n-2)+4)+ 4 = 4T(n-2)+ 12 = 4(2T(n-3)+4)+ 12 = 8T(n-3)+ 28 = 8(2T(n

问题 Closed . This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed 6 years ago . Can someone please help me understand this solution, and by help I mean help me iterate through everything so someone as stupid as I can understand it. Thank you so much :( public void recurse(int n, char one, char two, char three) { if(n == 1) System.out.println(n + " " + one + " " + two); else {

问题 Since non-tail recursion calls use stack frames like Java does, I'd think you'd be using it very sparingly, if at all. This seems however severely restrictive given it's one of the most important tools. When can I use non-tail recursion functions? Also, are there plans to remove the memory restriction in the future? 回答1: In the same situations where it would be safe in Java, where the dataset you are working with never grows huge and the performance isn't critical/hot path of your app. Also,

问题 This is a simple homework question, but I've been unable to solve it and honestly am wondering if it's even possible within the parameters that have been set. #include <iostream> using namespace std; void triangle(int m, int n); void drawline(char symbol, int len); int main() { triangle(3,5); return 0; } // ----------------------------------------------------------------------------- void triangle(int m, int n) { // use recursion to complete this function } // --------------------------------

问题 this code: $(document).ready(function() { $('body').click(function(evt) { if(evt.target.nodeName === 'A' && $(evt.target).hasClass('cross-link')) { $('a[href=#2]').trigger('click'); } });}); given me and error of "too much recursion" one might think that I should just attach a handler to the crosslink element. i tried this, but I couldn't get it to work because the DOM loads before the cross-link class elements are created. what do I need to do to fix this or do you have a better idea of what

问题 Now i can implement sqlite3 3.8.4.3 within my android app, i found an awesome library name sqlcipher , :) and now here again i'm trying to implement recursive function within an android app; i try (recursive function) from 'cmd' windows: i create a table : CREATE TABLE tree( id_tree integer PRIMARY KEY AUTOINCREMENT, id_boss TEXT, id_child TEXT, answ TEXT); insert some value : INSERT INTO tree(id_boss,id_child,answ) VALUES('1','2','T'); INSERT INTO tree(id_boss,id_child,answ) VALUES('1','3',

问题 I am just starting to learn java on my own by reading a book and completing the exercises. One of the exercises on the book is asking me to write a method that prints symmetric integer sequences using recursion. For example: writeSequence(1); //prints 1 writeSequence(2); //prints 1 1 writeSequence(3); //prints 2 1 2 writeSequence(4); //prints 2 1 1 2 writeSequence(5); //prints 3 2 1 2 3 writeSequence(6); //prints 3 2 1 1 2 3 So far, my solution uses two method implementations and doesn't look