Difference between revisions of "ECNU XCPC Team Training Round"

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(Created page with "== Problem A == Unsolved. == Problem B == Solved by yanghong. 04:34 (+) 类似数位dp的想法: 从高位到低位枚举, 如果小于边界则直接计算答案, 等...")
 
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Solved by yanghong. 04:34 (+)
 
Solved by yanghong. 04:34 (+)
 
类似数位dp的想法: 从高位到低位枚举, 如果小于边界则直接计算答案, 等于边界则固定此位置的值然后去低位计算
 
  
 
== Problem C ==
 
== Problem C ==

Revision as of 08:00, 23 December 2020

Problem A

Unsolved.

Problem B

Solved by yanghong. 04:34 (+)

Problem C

Solved by bingoier. 00:35 (+)

质因数分解后发现答案为每一个质数的指数 $k,((k+2)*(k+1)/2$ 的乘积之和

Problem D

Unsolved.

Problem E

Solved by bingoier. 01:17 (+1)

模拟题,将时间转化为秒数可以简便运算

Problem F

Solved by yanghong. 01:06 (+)

计算树上路径交

Problem G

Unsolved.

Problem H

Solved by Once. 03:08 (+2)

大概可以猜测一下,一个积木盘只有绕一圈之后才会出现一个轮换。所以我们就暴力把原来的积木标号之后转一圈,得到所有轮换,求出轮换的最小公倍数就是答案。然而模数不是素数,所以答案需要处理出所有的质因子后暴力相乘。

不过还有一个结论感觉很对但是不会证明,就是经过一个轮换之后积木形状相同。

时间复杂度 $O(n^2)$。

Problem I

Unsolved.

Problem J

Solved by bingoier. 00:07 (+)

签到,将题面上的代码复制过来即可