量力而行...
DP: https://codeforces.com/problemset?tags=dp,2100-2400
数据结构:https://codeforces.com/problemset?tags=data%20structures,2100-2400
线段树:https://blog.nowcoder.net/n/5d8e3519469b48bcb2bc76f7c8ecbab2
dp: https://blog.nowcoder.net/n/e84e0c8717a9484fb47a249bc0c8cacb