https://vjudge.net/problem/HDU-4870 pass(hint:This is a Expected DP)

https://www.luogu.com.cn/problem/P4178 pass(这是一个模板题)

https://vjudge.net/problem/HDU-4871 pass(感谢大佬帮我debug.)

https://vjudge.net/problem/HDU-4918 pass(虽然是点分树的模板题,但是我觉得挺难的)

https://vjudge.net/problem/HDU-5469

https://vjudge.net/problem/HDU-5977

https://vjudge.net/problem/HDU-6201

https://vjudge.net/problem/HDU-6268

https://vjudge.net/problem/HDU-6881

https://www.luogu.com.cn/problem/CF293E

https://vjudge.net/problem/SPOJ-FTOUR2

https://www.acwing.com/problem/content/254/