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
2020-07-06 23:14:47
waah. multisource bfs is best.
2020-06-19 21:44:06
AC in one go ! Multisource BFS :)
2020-06-19 16:45:24
AC in one go
2020-06-16 10:03:06
can be done without multisource bfs using only bfs shortest path with a little optimization ran in 0.5 s
although using multisource bfs ran in 0.03 s

Last edit: 2020-06-16 10:24:13
2020-05-31 08:44:05
simple mutisource bfs question :)
2020-05-28 14:52:57
Please take care after output each test, you need to read a empty line after every output, otherwise you gonna get RE
2020-05-14 07:30:52
who still could't solve the problem, just goto geeksforgeeks and read the article about multisouce bfs and solve the problem.... :)
2020-05-14 06:50:24
what is the maximum value of t....? -_-
2020-05-09 20:03:17
Simple logic. You can solve without bfs and dfs.
2020-04-25 08:38:58
if you're using multisource bfs keep in mind don't use pair,map etc. theres high chances that you will get TLE. And also no need of visited{true} array.
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