How to reverse a linked list in C is not hacker _news_.<p>Additionally, sites like these are a disease. At work, I overheard a phone screen in which the interviewer asked the question, "you have a collection of numbers, all of which appear twice, except one number which appears a single time. How do you find the number?" The person being interviewed gave the "clever" answer (xor all numbers together, result is your answer) within seconds. The interviewer said, "that's nice, but not what I'm going for. What if it's a collection of strings?" She couldn't do it.