Difference between revisions of "2018 Multi-University, Nowcoder Day 7"
Jump to navigation
Jump to search
(Created page with "== Problem A == Solved by zerol. 00:22 (+) == Problem B == == Problem C == Solved by ultmaster. 02:14 (+3) == Problem D == Unsolved. (-1) == Problem E == Solved by ult...") |
|||
| Line 8: | Line 8: | ||
Solved by ultmaster. 02:14 (+3) | Solved by ultmaster. 02:14 (+3) | ||
| + | |||
| + | 题意：给一个长度为 $2^n$ 的字符串，每次用 AND, OR, XOR 中的一种操作把相邻的两个合并。求最后合并结果是 1 的操作方案数。 | ||
| + | |||
| + | 题解：暴力就好了，维护一个可选的集合，和集合中每个产生的方案数。复杂度是 $\sum_{x=0}^{18} 2^{18 - x} \cdot \min(3^x, 2^{18-x}) \approx 1.4 \times 10^7$。由于还要带上数据结构的常数 / log，可能时限很紧。需要常数优化，能少开的地方尽量少开，unordered_map 可以卡过。 | ||
== Problem D == | == Problem D == | ||
Revision as of 12:23, 9 August 2018
Problem A
Solved by zerol. 00:22 (+)
Problem B
Problem C
Solved by ultmaster. 02:14 (+3)
题意：给一个长度为 $2^n$ 的字符串，每次用 AND, OR, XOR 中的一种操作把相邻的两个合并。求最后合并结果是 1 的操作方案数。
题解：暴力就好了，维护一个可选的集合，和集合中每个产生的方案数。复杂度是 $\sum_{x=0}^{18} 2^{18 - x} \cdot \min(3^x, 2^{18-x}) \approx 1.4 \times 10^7$。由于还要带上数据结构的常数 / log，可能时限很紧。需要常数优化，能少开的地方尽量少开，unordered_map 可以卡过。
Problem D
Unsolved. (-1)
Problem E
Solved by ultmaster. 03:07 (+1)
Problem F
Problem G
Problem H
Unsolved. (-2)
Problem I
Unsolved. (-13)
Problem J
Solved by kblack. 01:38 (+2)