convex hull in max/min or DP problems


Functions:

https://nanti.jisuanke.com/t/41094

https://nanti.jisuanke.com/t/41097

DP:

http://acm.zjnu.edu.cn/CLanguage/showproblem?problem_id=1267

http://acm.zjnu.edu.cn/CLanguage/showproblem?problem_id=1189

http://acm.zjnu.edu.cn/CLanguage/showproblem?problem_id=1362