BITMAP - Bitmap

There is given a rectangular bitmap of size n*m. Each pixel of the bitmap is either white or black, but at least one is white. The pixel in i-th line and j-th column is called the pixel (i,j). The distance between two pixels p1=(i1,j1) and p2=(i2,j2) is defined as:

d(p1,p2)=|i1-i2|+|j1-j2|.

Task

Write a program which:

  • reads the description of the bitmap from the standard input,
  • for each pixel, computes the distance to the nearest white pixel,
  • writes the results to the standard output.

Input

The number of test cases t is in the first line of input, then t test cases follow separated by an empty line. In the first line of each test case there is a pair of integer numbers n, m separated by a single space, 1<=n <=182, 1<=m<=182. In each of the following n lines of the test case exactly one zero-one word of length m, the description of one line of the bitmap, is written. On the j-th position in the line (i+1), 1 <= i <= n, 1 <= j <= m, is '1' if, and only if the pixel (i,j) is white.

Output

In the i-th line for each test case, 1<=i<=n, there should be written m integers f(i,1),...,f(i,m) separated by single spaces, where f(i,j) is the distance from the pixel (i,j) to the nearest white pixel.

Example

Sample input:
1
3 4
0001
0011
0110

Sample output:
3 2 1 0
2 1 0 0
1 0 0 1

Added by:Piotr Ɓowiec
Date:2004-09-13
Time limit:4s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All
Resource:6th Polish Olympiad in Informatics, stage 2

hide comments
2017-02-14 12:42:59
must try, learned a lot from this single problem :)
2017-02-06 05:40:43
Very good question for learning bfs!!
don't try brute force method ,try to solve by using bfs!!
2017-01-25 15:35:48
Good Question to learn BFS on matrix...
Deserves my upvote
2017-01-21 16:00:38
the trick was not to use multiple bfs calls :/
2017-01-06 10:31:21
Nice one .Do try it!
2016-12-25 17:09:05
BFS did it !
superb question ! must do <3
2016-12-08 08:31:41
Brute force worked..!!
Time limit is huge..
2016-10-07 12:38:10
:D enjoyed
2016-10-02 12:16:37
BFS
recursion may not pass
2016-09-17 22:19:09
No need to use bfs. Brute forced my way to 0.06s B|
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