Difference between revisions of "2018 Multi-University, Nowcoder Day 8"
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(Created page with "== Problem A == == Problem B == Solved by ultmaster. 01:12 (+) == Problem C == == Problem D == == Problem E == Solved by ultmaster. 03:12 (+) == Problem F == == Proble...") |
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== Problem B == | == Problem B == | ||
| − | Solved by | + | Solved by OEIS. 01:12 (+) |
| + | |||
| + | Brute force by ultmaster. | ||
| + | |||
| + | 题意：染棋盘上不同行不同列的 $n$ 个格子，使得经过一系列两个相邻格子都染黑则染黑的操作之后，所有格子都能染黑。 | ||
| + | |||
| + | 题解：$a_n = \frac{1}{n} \sum_{k=0}^n 2^k \binom{n}{k} \binom{n}{k-1}$。 | ||
== Problem C == | == Problem C == | ||
Revision as of 11:07, 11 August 2018
Problem A
Problem B
Solved by OEIS. 01:12 (+)
Brute force by ultmaster.
题意：染棋盘上不同行不同列的 $n$ 个格子，使得经过一系列两个相邻格子都染黑则染黑的操作之后，所有格子都能染黑。
题解：$a_n = \frac{1}{n} \sum_{k=0}^n 2^k \binom{n}{k} \binom{n}{k-1}$。
Problem C
Problem D
Problem E
Solved by ultmaster. 03:12 (+)
Problem F
Problem G
Solved by kblack. 00:13 (+)
Problem H
Solved by zerol & ultmaster. 02:47 (+6)