- Duplicate an linked list without using extra space(except the usage for duplicated list).
- Duplicate an linked list which has a random pointer
- Give a string containing alphabet character and a question mark
?and another dictionary which records what character(s) the question mark
?can be replaced to, and for each replacement, how much you need to pay for this replacement. You need to find given a string whether it can be turned to a palindrome with replacement or not and also return the minimum cost among all the replacement.
- Design a register system, where the system provides API like
sendConfirmation. However, due to the event size limit, only some of the registered users can be selected and the users are ranked by their register time. To design such a system to make the best performance.