2017-2018 ACM-ICPC East Central North America Regional Contest (ECNA 2017)

Problem A

Solved by ultmaster. 04:33 (+)

Problem B

Solved by kblack. 03:18 (+1)

题意：给定 $N$ 个圆，求包围图形的最小周长。

题解：类似凸包的 $O(nh)$ 算法，每次寻找包围图形上下一个点，通过角度的变化计算弧线的长度，注意处理圆包含等情况。

Problem C

Solved by zerol. 00:09 (+)

温暖的签到。

Problem D

Solved by kblack. 00:21 (+)

温暖的签到。

Problem E

Solved by ultmaster. 01:09 (+3)

Problem F

Solved by kblack. 01:04 (+)

温暖的树形签到。

Problem G

Solved by kblack. 01:31 (+)

温暖的 DP 签到。

Problem H

Solved by zerol. 00:17 (+)

Problem I

Solved by ultmaster. 02:17 (+)

Problem J

Solved by zerol. 01:22 (+)