Talk:Topological sort: Difference between revisions
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→alternate implementation
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: [http://paddy3118.blogspot.com/2009/09/j-for-py-guy.html J for a Py Guy] --[[User:Paddy3118|Paddy3118]] 17:37, 2 September 2009 (UTC)
Note: Roger Hui has pointed out that, in the version of J I am using (version 6.02a), the expression <code>;@:{L:0 1~</code> is slow on large data sets (for example: trees with 2e5 nodes). For now, a faster (but more obscure) implementation of the same algorithm is <code>3 : '(*c) #^:_1 (I.c) <@;/. (;y){y [ c=. #&> y'</code>. In both cases, we are finding the grandchildren which correspond to the current children. [[User:Rdm|Rdm]] 18:21, 2 September 2009 (UTC)
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