Codeforces Round 217 (Div. 2)
D
Broken Monitor
Codeforces
2100
原题
← CE →
翻译中…

Innocentius has a problem — his computer monitor has broken. Now some of the pixels are "dead", that is, they are always black. As consequence, Innocentius can't play the usual computer games. He is recently playing the following game with his younger brother Polycarpus.

翻译中…

Innocentius is touch-typing a program that paints a white square one-pixel wide frame on the black screen. As the monitor is broken, some pixels that should be white remain black. Polycarpus should look at what the program displayed on the screen and guess the position and size of the frame Innocentius has painted. Polycarpus doesn't like the game but Innocentius persuaded brother to play as "the game is good for the imagination and attention".

翻译中…

Help Polycarpus, automatize his part in the gaming process. Write the code that finds such possible square frame that:

翻译中…
  • the frame's width is 1 pixel,
  • the frame doesn't go beyond the borders of the screen,
  • all white pixels of the monitor are located on the frame,
  • of all frames that satisfy the previous three conditions, the required frame must have the smallest size.
翻译中…

Formally, a square frame is represented by such pixels of the solid square, that are on the square's border, that is, are not fully surrounded by the other pixels of the square. For example, if the frame's size is $*d* = 3$, then it consists of 8 pixels, if its size is $*d* = 2$, then it contains 4 pixels and if $*d* = 1$, then the frame is reduced to a single pixel.

翻译中…

Input

翻译中…

The first line contains the resolution of the monitor as a pair of integers $*n*$, $*m*$ ($1 ≤ *n*, *m* ≤ 2000$). The next $*n*$ lines contain exactly $*m*$ characters each — the state of the monitor pixels at the moment of the game. Character "." (period, ASCII code 46) corresponds to the black pixel, and character "w" (lowercase English letter w) corresponds to the white pixel. It is guaranteed that at least one pixel of the monitor is white.

翻译中…

Output

翻译中…

Print the monitor screen. Represent the sought frame by characters "+" (the "plus" character). The pixels that has become white during the game mustn't be changed. Print them as "w". If there are multiple possible ways to position the frame of the minimum size, print any of them.

翻译中…

If the required frame doesn't exist, then print a single line containing number -1.

翻译中…

Note

翻译中…

In the first sample the required size of the optimal frame equals 4. In the second sample the size of the optimal frame equals 3. In the third sample, the size of the optimal frame is 1. In the fourth sample, the required frame doesn't exist.

翻译中…

样例

Input #1
4 8
..w..w..
........
........
..w..w..
Output #1
..w++w..
..+..+..
..+..+..
..w++w..
InputCopy OutputCopy
Input #2
5 6
......
.w....
......
..w...
......
Output #2
......
+w+...
+.+...
++w...
......
InputCopy OutputCopy
Input #3
2 4
....
.w..
Output #3
....
.w..
InputCopy OutputCopy
Input #4
2 6
w..w.w
...w..
Output #4
-1
InputCopy OutputCopy
题目信息
题号
370D
时间限制
2 s
内存限制
256 MB
标签
暴力
构造
贪心
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。