Ethflow Round 1 (Codeforces Round 1001, Div. 1 + Div. 2)
H
Galaxy Generator
Codeforces
3500
原题
← G→
翻译中…

In a two-dimensional universe, a star can be represented by a point $(x,y)$ on a two-dimensional plane. Two stars are directly connected if and only if their $x$ or $y$ coordinates are the same, and there are no other stars on the line segment between them. Define a galaxy as a connected component composed of stars connected directly or indirectly (through other stars).

翻译中…

For a set of stars, its value is defined as the minimum number of galaxies that can be obtained after performing the following operation for any (possibly, zero) times: in each operation, you can select a point $(x,y)$ without stars. If a star can be directly connected to at least $3$ stars after creating it here, then you create a star here.

翻译中…

You are given a $n\times n$ matrix $a$ consisting of $0$ and $1$ describing a set $S$ of stars. There is a star at $(x,y)$ if and only if $a_{x,y}=1$. Calculate the sum, modulo $10^9 + 7$, of the values of all non-empty subsets of $S$.

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Input

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The first line of input contains a single integer $t$ ($1 \leq t \leq 100$) — the number of test cases.

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For each test case, the first line contains a single integer $n$ ($1 \leq n \leq 14$) — the size of matrix $a$.

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Then $n$ lines follow; the $i$-th line contains a string $a_i$ of length $n$ — the $i$-th row of matrix $a$.

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It is guaranteed that the sum of $2^n$ over all test cases does not exceed $2^{14}$.

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Output

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For each test case, output the sum, modulo $10^9 + 7$, of the values of all non-empty subsets of $S$.

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Note

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In the first test case, $S$ is empty. $S$ has no non-empty subsets. So the answer is $0$.

翻译中…

In the second test case, $S = \{(1,2),(2,1)\}$. $S$ has $3$ non-empty subsets.

翻译中…
  • $\{(1,2)\}$ and $\{(2,1)\}$ — there is only one star in the set, forming $1$ galaxy.
  • $\{(1,2),(2,1)\}$ — two stars in the set are not connected, forming $2$ galaxies.
翻译中…

So the answer is $1+1+2=4$.

翻译中…

In the third test case, $S = \{(1,2),(3,1),(3,3)\}$. $S$ has $7$ non-empty subsets.

翻译中…
  • $\{(1,2)\}$, $\{(3,1)\}$, and $\{(3,3)\}$ — there is only one star in the set, forming $1$ galaxy.
  • $\{(1,2),(3,1)\}$ and $\{(1,2),(3,3)\}$ — two stars in the set are not connected, forming $2$ galaxies.
  • $\{(3,1),(3,3)\}$ — two stars in the set are connected, forming $1$ galaxy.
  • $\{(1,2),(3,1),(3,3)\}$ — initially, star $(1,2)$ is not in the galaxy formed by $(3,1)$ and $(3,3)$. You can make an operation creating a star at $(3,2)$ connecting to these three stars, forming $1$ galaxy.
翻译中…

So the answer is $1+1+1+2+2+1+1=9$.

翻译中…

样例

Input #1
8
1
0
2
01
10
3
010
000
101
4
0110
1001
1001
0110
11
11111110111
10000010010
10111010011
10111010011
10111010001
10000010000
11111110101
00000000111
11011010011
10010101100
11101010100
11
11011111110
10010000010
00010111010
10010111010
01010111010
11010000010
01011111110
11000000000
01010000010
01000111100
00000001010
11
11010101001
11001010100
00000000110
11111110010
10000010010
10111010110
10111010111
10111010010
10000010110
11111110100
00000000000
3
111
100
111
Output #1
0
4
9
355
593092633
438667113
922743932
155
InputCopy OutputCopy
题目信息
题号
2062H
时间限制
4 s
内存限制
512 MB
标签
位运算
组合数学
动态规划

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。