wjm学长给的题

树上dp

https://codeforces.com/gym/103119/problem/I

https://codeforces.com/gym/103447/problem/C

https://codeforces.com/gym/103446/problem/G

https://codeforces.com/gym/104008/problem/G

https://codeforces.com/gym/103729/problem/L segmenttree

https://codeforces.com/gym/103729/problem/J

https://codeforces.com/gym/103729/problem/C

https://codeforces.com/gym/103729/problem/F

https://codeforces.com/gym/103729/problem/A

https://codeforces.com/gym/103729/problem/E

https://codeforces.com/contest/1701

https://acm.hdu.edu.cn/showproblem.php?pid=6989

https://atcoder.jp/contests/abc248/tasks/abc248_g

https://atcoder.jp/contests/abc248/tasks/abc248_h

https://ac.nowcoder.com/acm/contest/37344/D