P7772 [CF1667F] Yin Yang
NOI
题目描述

You are given a rectangular grid with $n$ rows and $m$ columns. $n$ and $m$ are divisible by $4$. Some of the cells are already colored black or white. It is guaranteed that no two colored cells share a corner or an edge.

Color the remaining cells in a way that both the black and the white cells becomes orthogonally connected or determine that it is impossible.

Consider a graph, where the black cells are the nodes. Two nodes are adjacent if the corresponding cells share an edge. If the described graph is connected, the black cells are orthogonally connected. Same for white cells.

Input

The input consists of multiple test cases. The first line of the input contains a single integer $t$ ($1 \le t \le 4000$) — the number of test cases. The description of the test cases follows.

The first line of each test case contains two integers $n$, $m$ ($8 \le n, m \le 500$, $n$ and $m$ are divisible by $4$) — the number of rows and columns.

Each of the next $n$ lines contains $m$ characters. Each character is either 'B', 'W' or '.', representing black, white or empty cell respectively. Two colored (black or white) cell does not share a corner or an edge.

It is guaranteed that the sum of $n \cdot m$ over all test cases does not exceed $250\,000$.

Output

For each testcase print "NO" if there is no solution, otherwise print "YES" and a grid with the same format. If there are multiple solutions, you can print any.

输入格式

见题面 Input 部分

输出格式

见题面 Output 部分

样例输入
4 8 8 .W.W.... .....B.W .W.W.... .....W.W B.B..... ....B.B. B.W..... ....B.B. 8 8 B.W..B.W ........ W.B..W.B ........ ........ B.W..B.W ........ W.B..W.B 8 12 W.B......... ....B...B.W. B.B......... ....B...B.B. .B.......... ........B... .W..B.B...W. ............ 16 16 .W............W. ...W..W..W.W.... .B...........B.W ....W....W...... W......B....W.W. ..W.......B..... ....W...W....B.W .W....W....W.... ...B...........W W.....W...W..B.. ..W.W...W......B ............W... .W.B...B.B....B. .....W.....W.... ..W......W...W.. W...W..W...W...W
样例输出
YES BWWWWWWW BWBBBBBW BWBWWWBW BWBWBWBW BWBWBWBW BWBBBWBW BWWWWWBW BBBBBBBW NO YES WWBBBBBBBBBB BWWWBBBBBBWB BBBWBBBWWWWB BBBWBBBWBBBB BBBWBBBWBBBB BBBWWWWWBBBB BWWWBBBWWWWB BBBBBBBBBBBB YES WWWWWWWWWWWWWWWW WWWWWWWWWWWWWWWW WBBBBBBBBBBBBBWW WBBBWBWWWWBWWBWW WBBWWBBBWWBWWBWW WBWWWBWWWWBWWBWW WBBWWBBBWWBWWBWW WWBWWWWWWWWWWWWW WWBBBBBBBBBBBBWW WBBBWWWBWWWBWBWW WWWBWBBBWBBBWBBB WWWBWBWWWWWBWWBW WWWBWBBBWBBBWWBW WWWWWWWWWWWWWWWW WWWWWWWWWWWWWWWW WWWWWWWWWWWWWWWW
提示

Solution for test case 1:

Test case 2: one can see that the black and the white part can't be connected in the same time. So the answer is "NO".