BITMAP - Bitmap

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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

hide comments
scorpion_ajay: 2017-02-14 12:42:59

must try, learned a lot from this single problem :)

manish_hacked: 2017-02-06 05:40:43

Very good question for learning bfs!!
don't try brute force method ,try to solve by using bfs!!

nikunjsoni: 2017-01-25 15:35:48

Good Question to learn BFS on matrix...
Deserves my upvote

ashishsb95: 2017-01-21 16:00:38

the trick was not to use multiple bfs calls :/

aditya9125: 2017-01-06 10:31:21

Nice one .Do try it!

up79: 2016-12-25 17:09:05

BFS did it !
superb question ! must do <3

manish556: 2016-12-08 08:31:41

Brute force worked..!!
Time limit is huge..

hamjosh1: 2016-10-07 12:38:10

:D enjoyed

alaa_alrayes96: 2016-10-02 12:16:37

BFS
recursion may not pass

akshayvenkat: 2016-09-17 22:19:09

No need to use bfs. Brute forced my way to 0.06s B|


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