2020 CCPC Online Contest

Problem A

Unsolved.

Problem B

Solved by all. 02:24:09(+1)

每个节点向其某个质因子连边，之后所有素数向 $2$ 连边。答案即为区间自然数和加上区间素数和，用 min25 筛出即可。

Problem C

Solved by bingoier. 00:27:30

Problem E

Solved by yanghong. 00:36:01(+2)

Problem F

Solved by Once. 04:43:11(+4)

把所有边界点带入后方的连续函数验证连续性即可。

取消同步要人命。