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 ith line and jth column is called the pixel (i,j). The distance between two pixels p_{1}=(i_{1},j_{1}) and p_{2}=(i_{2},j_{2}) is defined as:
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 zeroone word of length m, the description of one line of the bitmap, is written. On the jth 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 ith 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
hide comments
ihuntuuu:
20220127 08:02:42
Multisource BFS ! 

fahd_hakem:
20211031 21:37:29
Ac in one go 

musky:
20210806 06:26:54
Ac In One Go. Wooow. This is the simplest question. You have to just apply brut force approach. 

yasser1110:
20210716 13:49:00
Really nice problem! Good thing it doesn't have tags. Last edit: 20210716 13:49:27 

rec28:
20210615 17:58:23
ac one people should die in peace !! 

wslord:
20201229 21:05:32
Loved this question.... Take care, priority queue is not needed ;) 

kanishkverma_1:
20201117 17:29:49
If ur having NZEC in java then try the same solution in c++ . Worked like a charm for me. :P 

varuntumbe:
20201023 10:01:08
one good optimization is needed in multi source bfs. calculate the no of iterations and compare. 

gnomegeek:
20200804 23:42:49
No need to use BFS. Applyting Brute Force works. AC in one go. 

satish7978:
20200706 23:14:47
waah. multisource bfs is best. 
Added by:  Piotr Ćowiec 
Date:  20040913 
Time limit:  4s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All 
Resource:  6th Polish Olympiad in Informatics, stage 2 