Codeforces Round 470 (rated, Div. 2, based on VK Cup 2018 Round 1)
A
Protect Sheep
Codeforces
900
原题
←B →
翻译中…

Bob is a farmer. He has a large pasture with many sheep. Recently, he has lost some of them due to wolf attacks. He thus decided to place some shepherd dogs in such a way that all his sheep are protected.

翻译中…

The pasture is a rectangle consisting of $*R* × *C*$ cells. Each cell is either empty, contains a sheep, a wolf or a dog. Sheep and dogs always stay in place, but wolves can roam freely around the pasture, by repeatedly moving to the left, right, up or down to a neighboring cell. When a wolf enters a cell with a sheep, it consumes it. However, no wolf can enter a cell with a dog.

翻译中…

Initially there are no dogs. Place dogs onto the pasture in such a way that no wolf can reach any sheep, or determine that it is impossible. Note that since you have many dogs, you do not need to minimize their number.

翻译中…

Input

翻译中…

First line contains two integers $*R*$ ($1 ≤ *R* ≤ 500$) and $*C*$ ($1 ≤ *C* ≤ 500$), denoting the number of rows and the numbers of columns respectively.

翻译中…

Each of the following $*R*$ lines is a string consisting of exactly $*C*$ characters, representing one row of the pasture. Here, 'S' means a sheep, 'W' a wolf and '.' an empty cell.

翻译中…

Output

翻译中…

If it is impossible to protect all sheep, output a single line with the word "No".

翻译中…

Otherwise, output a line with the word "Yes". Then print $*R*$ lines, representing the pasture after placing dogs. Again, 'S' means a sheep, 'W' a wolf, 'D' is a dog and '.' an empty space. You are not allowed to move, remove or add a sheep or a wolf.

翻译中…

If there are multiple solutions, you may print any of them. You don't have to minimize the number of dogs.

翻译中…

Note

翻译中…

In the first example, we can split the pasture into two halves, one containing wolves and one containing sheep. Note that the sheep at (2,1) is safe, as wolves cannot move diagonally.

翻译中…

In the second example, there are no empty spots to put dogs that would guard the lone sheep.

翻译中…

In the third example, there are no wolves, so the task is very easy. We put a dog in the center to observe the peacefulness of the meadow, but the solution would be correct even without him.

翻译中…

样例

Input #1
6 6
..S...
..S.W.
.S....
..W...
...W..
......
Output #1
Yes
..SD..
..SDW.
.SD...
.DW...
DD.W..
......
InputCopy OutputCopy
Input #2
1 2
SW
Output #2
No
InputCopy OutputCopy
Input #3
5 5
.S...
...S.
S....
...S.
.S...
Output #3
Yes
.S...
...S.
S.D..
...S.
.S...
InputCopy OutputCopy
题目信息
题号
948A
时间限制
1 s
内存限制
256 MB
标签
暴力
DFS 及类似
图论
模拟

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。