AtCoder Grand Contest 003
F
Fraction of Fractal
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⌀ 3344
原题
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翻译中…

Problem Statement

翻译中…

Snuke got a grid from his mother, as a birthday present. The grid has $H$ rows and $W$ columns. Each cell is painted black or white. All black cells are 4-connected, that is, it is possible to traverse from any black cell to any other black cell by just visiting black cells, where it is only allowed to move horizontally or vertically.

翻译中…

The color of the cell at the $i$-th row and $j$-th column $(1 ≦ i ≦ H, 1 ≦ j ≦ W)$ is represented by a character $s_{ij}$. If $s_{ij}$ is #, the cell is painted black. If $s_{ij}$ is ., the cell is painted white. At least one cell is painted black.

翻译中…

We will define fractals as follows. The fractal of level $0$ is a $1 × 1$ grid with a black cell. The fractal of level $k+1$ is obtained by arranging smaller grids in $H$ rows and $W$ columns, following the pattern of the Snuke's grid. At a position that corresponds to a black cell in the Snuke's grid, a copy of the fractal of level $k$ is placed. At a position that corresponds to a white cell in the Snuke's grid, a grid whose cells are all white, with the same dimensions as the fractal of level $k$, is placed.

翻译中…

You are given the description of the Snuke's grid, and an integer $K$. Find the number of connected components of black cells in the fractal of level $K$, modulo $10^9+7$.

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Constraints

翻译中…
  • $1 ≦ H,W ≦ 1000$
  • $0 ≦ K ≦ 10^{18}$
  • Each $s_{ij}$ is either # or ..
  • All black cells in the given grid are 4-connected.
  • There is at least one black cell in the given grid.
翻译中…

Input

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The input is given from Standard Input in the following format:

翻译中…

H W K
s_{11} .. s_{1W}
:
s_{H1} .. s_{HW}

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Output

翻译中…

Print the number of connected components of black cells in the fractal of level $K$, modulo $10^9+7$.

翻译中…

样例

Input #1
3 3 3
.#.
###
#.#
Output #1
20
The fractal of level $K=3$ in this case is shown below. There are $20$ connected components of black cells.
Input #2
3 3 3
###
#.#
###
Output #2
1
Input #3
11 15 1000000000000000000
.....#.........
....###........
....####.......
...######......
...#######.....
..##.###.##....
..##########...
.###.....####..
.####...######.
###############
#.##..##..##..#
Output #3
301811921
题目信息
题号
agc003_f
时间限制
2 s
内存限制
256 MB

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