PLUSEVI - How Many Plusses
Mirko is a strange boy so he has written down a square matrix full of ones and zeroes. Now he is interested in how many plusses there are in his matrix.
A plus is a square such that its side has an odd length greater than 1 and all of its cells are zero, except for the middle row and the middle column: they must be full of ones. For example, in the matrix below there are two plusses, one inside the other:
00100
00100
11111
00100
00100
Input
In the first line there is an integer N ≤ 2000, dimension of the square matrix.
The next N lines are the rows of the matrix.
Output
Print the number of plusses appearing in the matrix.
Example
Input: 8
00010000
00010000
00010000
11111111
00010000
00010010
00010111
00010010
Output: 3
hide comments
(Tjandra Satria Gunawan)(曾毅昆):
2012-12-25 15:48:03
@Ehor Nechiporenko: No, that not true... Max matix size is 2000x2000. AC on first try with 2000x2000 static array... |
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Ehor Nechiporenko:
2012-12-24 15:23:01
Important!!! Seems like matrix size could be greater than 200!
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Radhakrishnan Venkataramani:
2011-09-14 09:33:35
Nice Problem !!!
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Added by: | Adrian Satja Kurdija |
Date: | 2011-05-21 |
Time limit: | 1s-4.595s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ASM64 |
Resource: | Croatian junior team selection test 2011 |