recursion

问题 I have the following array (that's actually coming from a backend service): const flat: Item[] = [ { id: 'a', name: 'Root 1', parentId: null }, { id: 'b', name: 'Root 2', parentId: null }, { id: 'c', name: 'Root 3', parentId: null }, { id: 'a1', name: 'Item 1', parentId: 'a' }, { id: 'a2', name: 'Item 1', parentId: 'a' }, { id: 'b1', name: 'Item 1', parentId: 'b' }, { id: 'b2', name: 'Item 2', parentId: 'b' }, { id: 'b2-1', name: 'Item 2-1', parentId: 'b2' }, { id: 'b2-2', name: 'Item 2-2',

问题 I have the following array (that's actually coming from a backend service): const flat: Item[] = [ { id: 'a', name: 'Root 1', parentId: null }, { id: 'b', name: 'Root 2', parentId: null }, { id: 'c', name: 'Root 3', parentId: null }, { id: 'a1', name: 'Item 1', parentId: 'a' }, { id: 'a2', name: 'Item 1', parentId: 'a' }, { id: 'b1', name: 'Item 1', parentId: 'b' }, { id: 'b2', name: 'Item 2', parentId: 'b' }, { id: 'b2-1', name: 'Item 2-1', parentId: 'b2' }, { id: 'b2-2', name: 'Item 2-2',

问题 I have the following array (that's actually coming from a backend service): const flat: Item[] = [ { id: 'a', name: 'Root 1', parentId: null }, { id: 'b', name: 'Root 2', parentId: null }, { id: 'c', name: 'Root 3', parentId: null }, { id: 'a1', name: 'Item 1', parentId: 'a' }, { id: 'a2', name: 'Item 1', parentId: 'a' }, { id: 'b1', name: 'Item 1', parentId: 'b' }, { id: 'b2', name: 'Item 2', parentId: 'b' }, { id: 'b2-1', name: 'Item 2-1', parentId: 'b2' }, { id: 'b2-2', name: 'Item 2-2',

问题 I have a simple method I've written for a class homework assignment that uses recursion (yes, it must use recursion) to calculate the number of triangles in a fractal pattern: public static BigInteger triangleFract(int layer) { if(layer < 0) { throw new IllegalArgumentException("Input must be >= 0"); } else if(layer == 0) { return new BigInteger("0"); } else if (layer == 1) { return new BigInteger("1"); } else { return triangleFract(layer - 1) .multiply(new BigInteger("3")) .add(new

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 7 months ago . I'm doing this problem called "Unique Paths" on a site called leetcode. The problem is: given a 2D matrix with 1s and 0s, a robot starts at the top-left and wants to reach the bottom-right. The robot has only 2 moves: right and down. Also, there are obstacles (represented by a '1'). The robot cannot walk over

问题 EDIT: I have rewritten this question to be much clearer. I am trying to programmatically infer an interface which references itself. I am writing some code which can encode a recursive structure in binary. For example: const myTreeEncoder = Struct(Self => ({ name: Str, children: List(Self) }); This can encode structures like this from binary and back: const someUint8Array = myTreeEncoder.encode({ name: 'parent', children: [{ name: 'child', children: [] }] }); The problem is, how can the

问题 I can't figure out how can I make this tail recursive Scheme function not tail recursive anymore. Anyone can help me? (define (foldrecl f x u) (if (null? x) u (foldrecl f (cdr x) (f (car x) u)))) 回答1: left folds are inheritly iterative, but you can easily make them recursive by adding a continuation. eg. (let ((value expresion-that-calculates)) value) So in your case: (define (foldrecl f x u) (if (null? x) u (let ((result (foldrecl f (cdr x) (f (car x) u)))) result))) While this looks

问题 I am trying to create a trigger which will update the grades of all the friends of a student whose grade is updated. create trigger upgrade after update on Highschooler when new.grade=old.grade+1 and trigger_nestlevel() < 2 begin update Highschooler set grade=new.grade where ID in ( select ID2 from Friend where ID1=old.ID ) ; end friends of friends (of friends...) of the person whose grade is increased are also being 'upgraded' how can i stop this? 回答1: As you can read in Limits In SQLite you

问题 I have an array which I created in php with a recursive function, I do not know how many dimensions, how can I use in Smarty ? I trying use this code : {foreach $myArr as $items} <li> {$items.title} {if $item.submenu} <ul> {foreach $items.submenu as $items2} <li>{$items2.title}</li> {/foreach} </ul> {/if} </li> {/foreach} But this code is for just 2 levels, may be my array have 3 or 4 or ... levels. UPDATE: I found the solution, in my solution I use Smarty functions : {function name=menu

问题 I'm new to programming, and I'm starting to read a book about it to understand the fundamentals. I couldn't understand how the following assembly code works: it calculates the factorial of a number. I have added comments to the instructions that I can understand - clearly I'm missing something. .section .data .section .text .globl _start .globl factorial _start: pushl $4 call factorial popl %ebx movl %eax, %ebx movl $1, %eax int $0x80 factorial: pushl %ebp # push the base pointer movl %esp,