デンソークリエイトプログラミングコンテスト2026(AtCoder Beginner Contest 443)
E
Climbing Silver
AtCoder
⌀ 1301
原题
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Problem Statement

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There is an $N \times N$ grid. The cell at the $i$-th row from the top and $j$-th column from the left is called $(i,j)$. The grid is described by $N$ strings $S_1,S_2,\dots,S_N$. If the $j$-th character of $S_i$ is ., $(i,j)$ is an empty cell; if it is #, $(i,j)$ is a wall cell.

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Initially, Takahashi-kun is at empty cell $(N,C)$, and repeats the following movement $N-1$ times:

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  • If he is currently at $(r,c)$, he specifies one of $(r-1,c-1),(r-1,c),(r-1,c+1)$ as the destination. Here, he cannot specify a cell that does not exist in the grid as the destination.
  • If the destination $(a,b)$ is a wall cell, the following occurs:
  • If $(i,b)$ is currently an empty cell for all integers satisfying $a < i \le N$, he destroys the wall at $(a,b)$ and moves there. That is, $(a,b)$ becomes an empty cell and he moves to $(a,b)$.
    • Otherwise, he fails to move. In this case, he immediately ends the repetition of movements, even if he has not made $N-1$ movements.
  • If the destination $(a,b)$ is an empty cell, he moves to $(a,b)$.
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Output a string $R$ of length $N$ satisfying the following conditions:

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  • If he can reach $(1,i)$ without failing during the movements, the $i$-th character of $R$ is 1.
  • Otherwise, the $i$-th character of $R$ is 0.
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You are given $T$ test cases; solve each of them.

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Constraints

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  • $T,N,C$ are integers.
  • $1 \le T \le 50000$
  • $2 \le N \le 3000$
  • $1 \le C \le N$
  • $S_i$ is a string of length $N$ consisting of . and #.
  • The $C$-th character of $S_N$ is ..
  • For each input, the sum of $N^2$ does not exceed $9 \times 10^6$.
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Input

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

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T
\text{case}_1
\text{case}_2
\vdots
\text{case}_T

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Each test case is given in the following format:

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N C
S_1
S_2
\vdots
S_N

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Output

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Print $T$ lines.

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The $i$-th line should contain the answer for the $i$-th test case.

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样例

Input #1
5
5 3
.###.
..#..
#.#.#
#...#
##..#
2 2
##
..
4 1
####
####
####
.###
3 3
...
...
...
10 3
##.##.##.#
.####..#..
...#.#..#.
.#.#.#.#..
...####...
#.#.##....
.##...#...
#.##.....#
#....###.#
.#..#.#...
Output #1
10111
11
1000
111
0011010010
This input contains five test cases. For the first test case, for example, he can reach $(1,3)$ without failing during the movements as follows: - Initially, he is at $(5,3)$. - He moves to empty cell $(4,2)$. - $(3,3)$ is a wall cell, but since $(4,3),(5,3)$ are currently both empty cells, he destroys the wall at $(3,3)$ and moves to $(3,3)$. - $(2,3)$ is a wall cell, but since $(3,3),(4,3),(5,3)$ are currently all empty cells, he destroys the wall at $(2,3)$ and moves to $(2,3)$. - $(1,3)$ is a wall cell, but since $(2,3),(3,3),(4,3),(5,3)$ are currently all empty cells, he destroys the wall at $(1,3)$ and moves to $(1,3)$. He can reach $(1,1),(1,3),(1,4),(1,5)$ without failing during the movements, so print `10111`.
题目信息

题面与样例版权归 AtCoder 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。