2019/7/4

1175D - Array Splitting

1.区间和基本涉及 前缀和
2.1 2 3 4 5 6 7 ， 有着公差为1都良好性质

1175B Catch Overflow!

1.min(INF, cur); , 是处理边界最大值常用的方法

1167D Bicolored RBS

s 的贡献来源于s’字串 , d(s’)=sum ；
r,b的贡献来源于s’字串的子序列 , d®+d(b)=sum ；

1165E Two Arrays and Sum of Functions

This is the number of l and r such that a_i and b_i are going to
contribute to f(l, r). There are i possible left borders
(1,2,…,i),and n-i+1 right borders (i,i+1,…,n). We can choose those
borders independently, so the number of ways of doing this is
i*(n-i+1) according to the product rule.

遇到对应相乘 用 rearrangement inequality