Author: | A. Klenin | Time limit: | 2 sec | |
Input file: | input.txt | Memory limit: | 256 Mb | |
Output file: | output.txt |
The height map of some square country is represented with a matrix of N×N integers. Each integer reflects average height of the corresponding area. We will denote the height value at location (x,y) as h[x,y].
A location (x,y) is named depression if for all x′=x−W…x+W,y′=y−W…y+W location (x′,y′) is also inside of the map and h[x,y]≤h[x′,y′].
Your program must find coordinates of all depressions of the given height map.
Input file contains integers NW, followed by N×N integers — location heights, row-by-row.
Output file must contain an integer M — number of possible depressions, followed by M pairs of integers xiyi, where xi — the column of the i-th depression, yi — the row of the i-th depression. Numbering starts from 1.
Depressions must be ordered by y, then by x.
3≤N≤500
1≤W
2×W<N
1≤h[x,y]≤1000
No. | Input file (input.txt ) |
Output file (output.txt ) |
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1 |
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2 |
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