英文面试，30分钟左右，小姐姐很nice
1. What is hashmap
2. What if two key has same hash - When two unequal objects have the same hash value, this causes a collision in the hash table, because both objects want to be in the sameslot (sometimes called a bucket).
3. Stack and heap
4. What is bst
5. Linkedlist and array
6. Quicksort
7. what is mem leak
8. Oop characteristis
9. Polymorphesim
10. Thread pool?
BQ：
1. tell me about yourself
2. how do you handle conflict
3. tell me about one project
