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
2020-04-10 15:49:53
Ac in one go :p
Simple multisource bfs with dijkstra.
2020-04-10 11:41:28
I am getting TLE repeatedly using multisource bfs i am not able to figure out the problem
2020-03-28 08:35:43
Ac in one go . Easy multisource bfs question.
2020-03-22 06:11:10
What's the complexity of the multisource bfs approach?
2020-01-15 13:18:36
for those having confusion in input format, you have to input n strings
2019-10-28 14:31:12
for who are getting SIGNALABRT (Runtime error) , your solution might be using more memory then available
2019-10-08 07:22:41
No need to use BFS, DFS simple logic work in O(n^2)
2019-09-28 06:47:41
good question, simple bfs... :) \|/
2019-08-30 11:19:02
Chooslo!!!!!!!!
2019-06-02 11:58:57
do only using multisource bfs,it is nothing but you have to push all source vertices with distance 0 and all same as djikstra
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