题目描述

Prof. Pang is given an $n\times m$ board. Some cells are colored black, some cells are colored white, and others are uncolored.

Prof. Pang doesn't like $\textbf{check patterns}$, so he wants to color all uncolored cells such that there is no check pattern on the board.

$4$ cells forming a $2\times 2$ square are said to have the check pattern if they are colored in one of the following ways:

BW
WB

WB
BW

Here W ("wakuda" in Chewa language) means the cell is colored black and B ("biancu" in Corsican language) means the cell is colored white.

输入格式

The first line contains a single integer $T$ $(1\leq T \leq 10^4)$ denoting the number of test cases.

The first line of each test case contains two integers $n$ and $m$ ($1\le n, m\le 100$) denoting the dimensions of the board.

Each of the next $n$ lines contains $m$ characters. The $j$-th character of the $i$-th line represents the status of the cell on the $i$-th row and $j$-th column of the board. The character is W if the cell is colored black, B if the cell is colored white, and ? if the cell is uncolored.

It is guaranteed that the sum of $nm$ over all test cases is no more than $10^6$.

输出格式

For each test case, output a line containing $\texttt{NO}$ if you cannot color all the uncolored cells such that there is no check pattern on the board.

Otherwise, output a line containing $\texttt{YES}$. In the next $n$ lines, output the colored board in the same format as the input. The output board should satisfy the following conditions.

• It does not have any check pattern.
• It consists of only $\texttt{B}$ and $\texttt{W}$.
• If a cell is already colored in the input, its color cannot be changed in the output.

If there are multiple solutions, output any of them.

题目大意

$n \times m$ 的棋盘，知道一些位置是黑色的，一些位置是白色的，一些位置不知道是什么颜色。

请你构造一种方案让棋盘的每个位置被染成黑色或白色（已知的位置不能换颜色），使得棋盘上不存在子矩阵：

BW
WB

以及

WB
BW

多组询问。

3
2 2
??
??
3 3
BW?
W?B
?BW
3 3
BW?
W?W
?W?

YES
BW
WW
NO
YES
BWB
WWW
BWB