算法 Algorithm
1. two pointers
2. binary search
binary tree & divide and conquer
3. backtracking / DFS / recursion BFS / union find
dynamic programming
greedy
4. sort / toplogical sort
5. math
bit manipulation
design
brainteaser
minimax
random
rejection sampling
reservoir sampling
memoization
数据结构 Data Structure
1. string
2. hash table
3. linked list
4. stack / queue / map / heap
5. tree / binary search tree / binary indexed tree / segment tree
6. trie
7. graph
8. geometry