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
nitishk24:
20180105 02:11:33
DP solution: Break in 2 parts, one traversal can pass traverses bottom right while another up left


frozen7:
20171220 09:02:47
simple multi source bfs question 

karthik1997:
20171217 17:39:51
Nice Problem Try using 2pass DP , (top down and bottom up passes ) and its complexity is O(M*N) . Would never go TLE , if m and n are increased by 100 folds => to 10000 , while bfs surely results in TLE. Last edit: 20171217 17:41:34 

sinersnvrsleep:
20171211 12:33:18
solved in o(n*m*(number_of_ones)) complexity ; 

ehsanhy:
20171210 13:48:31
Finally accepted :) 

malish_228:
20171208 17:47:17
hmm... 

malish_228:
20171204 18:53:44
easy joy 

anurag_tangri:
20171122 10:47:47
BFS :) calculate distance of black pixels by calling bfs from white pixels and get AC:) 

hanstan:
20171024 17:29:12
BFS 0.00s :D :D :D 

hitesh87:
20171019 11:45:22
Time limit is huge can be done using brute force with adjacency list. 
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 