The Big Programming Thread - Page 934

On January 03 2018 22:45 tofucake wrote:

Only ones I can think of are various subreddits (like /r/programming)

A lot of the individual sub reddits are good, depending on the language, hackernews is also pretty decent, though it's turning a bit redditish for my liking.

I despise /r/programming and loath /r/technology though.

On January 05 2018 02:12 sc-darkness wrote:
Could someone confirm if it's possible to reverse order of a singly linked list without using both directions (head and tail)? Just going forward basically. Is that possible without modifying internal data such as node (next/previous pointers) and just using std::swap? This is mostly about C++, but I think the question is generic anyway.

Apparently I failed an interview question about that, so I'm thinking my application of algorithms on the spot isn't so good without Google. Any advice how to get better?

On January 05 2018 02:58 Acrofales wrote:

It sounds possible, but horribly inefficient. You can swap the head with the tail, then the head + 1 with tail - 1, etc. etc.

Basically you do this:

a->b->c->d->e
e->b->c->d->a
e->d->c->b->a

all reversed. but it's O(n^2) for simply reversing a list (assuming no auxiliary datastructures). Yuck.

On January 05 2018 03:16 Blitzkrieg0 wrote:


Can you change the pointer on node d from e to a with only a singly linked list? The tail node shouldn't know what the previous node is in a singly linked list.

int a = 3;
int b = 5;

int* pa = &a;
int* pb = &b;


cout << a << ", " << b;
//output is 3, 5

std::swap(a, b);

cout << a << ", " << b;
//output is 5, 3

cout << *pa << ", " << *pb;
//output is 5, 3

On January 05 2018 06:48 sc-darkness wrote:
Well, you can always get someone better. What's the problem to train someone and offer them slightly lower salary at the beginning? You can't always employ fully experienced people (well, you can but at some point you'll run out of people). In my opinion, that's pretty much profit only and not much investment (full capitalism).

Remember that people need to grow their career after all. They're not born fully educated, fully experienced, etc.
IT industry always complains there aren't enough software developers. How can there be enough if they're not willing to train people when needed? If you enjoy a company but they expect too much, can't you be told to learn a bit while on a lower salary?

On January 04 2018 08:42 WarSame wrote:
I'm looking for all languages, as well as discussion on frameworks, technology, etc. I guess like a nerd site more devote to tech, with a focus on software/mechatronics.



Some of the individuals are good but I'm not interested enough in any one technology(yet) to want to dive that deep.

/r/programming has some good articles, but the discussion is generally not great and the ratio of good articles to bad is low.

/r/technology has a very low quality overall. If there were some higher-quality version of it(like /r/NeutralPolitics is to /r/politics) I think that might be my ideal.

I'll check out hackernews but I heard bad things about it before.

StackOverflow is too issue-focused for what I want.

What are good IRC or Discord channels? I'm assuming there's some Slack channels too?

On January 05 2018 03:16 Blitzkrieg0 wrote:


Can you change the pointer on node d from e to a with only a singly linked list? The tail node shouldn't know what the previous node is in a singly linked list.

On January 05 2018 14:06 Blisse wrote:


It's not that they don't hire less experienced programmers at all, it's that they really want to hire an experienced programmer. Sometimes there's no headcount for less experienced programmers because there's no room on the team for more junior people, i.e. nearing deadlines, no time to dedicate to training new hires, already have several juniors on team.

From an employer's perspective, it's hard to tell when someone's inexperienced but could be great, vs experienced and already decent. Why take the higher risk if you're not looking at hiring juniors?

On January 05 2018 02:12 sc-darkness wrote:
Could someone confirm if it's possible to reverse order of a singly linked list without using both directions (head and tail)? Just going forward basically. Is that possible without modifying internal data such as node (next/previous pointers) and just using std::swap? This is mostly about C++, but I think the question is generic anyway.

Apparently I failed an interview question about that, so I'm thinking my application of algorithms on the spot isn't so good without Google. Any advice how to get better?

v
a->b->c->d
         v
a<-b<-c<-d

template<typename T>
struct ListNode {
  ListNode* next;
  T data;
};

/*Takes the start of a singly linked list, returns the new start once it's been reversed*/
template<typename T>
ListNode<T>* reverseList(ListNode<T>* node) {
  ListNode<T>* prev = nullptr;
  ListNode<T>* next;

  while(node) {
    next = node->next;
    node->next = prev;
    prev = node;
    node = next;
  }  
  return prev;
}

On January 06 2018 16:56 dekibeki wrote:


we could reverse it by doing something like

v
a->b->c->d
         v
a<-b<-c<-d

You're just swapping the links, this can be done in O(n).
I don't use std::swap for my implementation below, but you could fit it in somewhere (squash prev/next into one variable and std::swap it with node->next?)
+ Show Spoiler +

std::swap(prev, node->next);
std::swap(prev, node);