Pls... help me out with this problem
http://www.spoj.com/problems/ANGELS/
It uses bipartite matching i guess. But am not able to build the graph .
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Pls... help me out with this problem
http://www.spoj.com/problems/ANGELS/
It uses bipartite matching i guess. But am not able to build the graph .
Название |
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Your guess is absolutely correct. Consider vertical and horizontal segments formed by adjacent symbols 'A' in every row and in every column. If we want to place a "fighter" in some square (i, j), we can't place any "fighter" in vertical and in horizontal segments that (i,j) belongs to.
So, we need to make a bipartite graph where vertices are segments and edges are squares (i,j) where we can place a "fighter".
Maximal matching in this graph is the answer for the problem.
got it.... :)
thnx a lot