Sunrise Software Engineer Interview Experience — Nine or Ten Rounds in One Chicago Onsite

You have to go to Chicago in person — I'm sick of it. The whole trip was a terrible experience. The interview process was long and painful, and after each round they'd ghost you for a month. But then when HR finally reached back out a month later, you had to give them a firm availability within a single day. The company's culture and technical bar didn't impress me either. They seem to have very low tolerance for new ideas. Avoid this one.

Question showcase:

• Singly linked list reverse

• For a square generated by a spiral, how do you quickly figure out what number is at position (x, y)?

• There are 100 light bulbs, numbered 1 to 100, all initially off. The first person toggles every bulb (off→on). The second person toggles every 2nd bulb (2, 4, 6...). The third person toggles every 3rd bulb (3, 6, 9...). And so on, until the 100th person toggles every 100th bulb. Which bulbs end up on?

• What's the difference between a class and a struct? Can a class have a reference as a member variable?

• Can a constructor be virtual?

• What's the difference between a pointer and a reference?

• Placement new

• Compare the performance of these two pieces of code.

  Code A:

  int *data = (int*)malloc(sizeof(int) * 64 * 1024 * 1024);
  for (int i = 0; i < 64 * 1024 * 1024; ++i) {
      data[i] += 1;
  }
  

  Code B:

  int *data = (int*)malloc(sizeof(int) * 64 * 1024 * 1024);
  for (int i = 0; i < 64 * 1024 * 1024; i += 8) {
      data[i] += 1;
  }
  

• In int (*s[10])(int), what type is s?

• What can access physical memory directly?

• Exactly how is shared_memory locked?

• Given a singly linked list where you only have a pointer to one node (not the head), how do you delete that node?

• Four people need to cross a river, and their individual crossing times are 1, 2, 5, and 6 minutes. How do you get everyone across within 13 minutes?

• Binary tree: determine whether it's a valid BST

• unordered_map vs map

• Linux networking, virtual memory, mutex vs condition variable, overloading vs overriding

• Least squares method

• An elementary-school arithmetic riddle: someone normally gets from school to the station to home and arrives at 5:00, but today they left an hour earlier and arrived at 4:48

• Interval merge

• Given an unordered array, what's the maximum gap between two adjacent elements once the array is sorted?

Yes, all of these were asked during the onsite. I honestly forget if it was nine or ten rounds total.