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Diffstat (limited to 'maxflow.h')
| -rw-r--r-- | maxflow.h | 95 |
1 files changed, 0 insertions, 95 deletions
diff --git a/maxflow.h b/maxflow.h deleted file mode 100644 index d490f45..0000000 --- a/maxflow.h +++ /dev/null @@ -1,95 +0,0 @@ -/* - * Edmonds-Karp algorithm for finding a maximum flow and minimum - * cut in a network. Almost identical to the Ford-Fulkerson - * algorithm, but apparently using breadth-first search to find the - * _shortest_ augmenting path is a good way to guarantee - * termination and ensure the time complexity is not dependent on - * the actual value of the maximum flow. I don't understand why - * that should be, but it's claimed on the Internet that it's been - * proved, and that's good enough for me. I prefer BFS to DFS - * anyway :-) - */ - -#ifndef MAXFLOW_MAXFLOW_H -#define MAXFLOW_MAXFLOW_H - -/* - * The actual algorithm. - * - * Inputs: - * - * - `scratch' is previously allocated scratch space of a size - * previously determined by calling `maxflow_scratch_size'. - * - * - `nv' is the number of vertices. Vertices are assumed to be - * numbered from 0 to nv-1. - * - * - `source' and `sink' are the distinguished source and sink - * vertices. - * - * - `ne' is the number of edges in the graph. - * - * - `edges' is an array of 2*ne integers, giving a (source, dest) - * pair for each network edge. Edge pairs are expected to be - * sorted in lexicographic order. - * - * - `backedges' is an array of `ne' integers, each a distinct - * index into `edges'. The edges in `edges', if permuted as - * specified by this array, should end up sorted in the _other_ - * lexicographic order, i.e. dest taking priority over source. - * - * - `capacity' is an array of `ne' integers, giving a maximum - * flow capacity for each edge. A negative value is taken to - * indicate unlimited capacity on that edge, but note that there - * may not be any unlimited-capacity _path_ from source to sink - * or an assertion will be failed. - * - * Output: - * - * - `flow' must be non-NULL. It is an array of `ne' integers, - * each giving the final flow along each edge. - * - * - `cut' may be NULL. If non-NULL, it is an array of `nv' - * integers, which will be set to zero or one on output, in such - * a way that: - * + the set of zero vertices includes the source - * + the set of one vertices includes the sink - * + the maximum flow capacity between the zero and one vertex - * sets is achieved (i.e. all edges from a zero vertex to a - * one vertex are at full capacity, while all edges from a - * one vertex to a zero vertex have no flow at all). - * - * - the returned value from the function is the total flow - * achieved. - */ -int maxflow_with_scratch(void *scratch, int nv, int source, int sink, - int ne, const int *edges, const int *backedges, - const int *capacity, int *flow, int *cut); - -/* - * The above function expects its `scratch' and `backedges' - * parameters to have already been set up. This allows you to set - * them up once and use them in multiple invocates of the - * algorithm. Now I provide functions to actually do the setting - * up. - */ -int maxflow_scratch_size(int nv); -void maxflow_setup_backedges(int ne, const int *edges, int *backedges); - -/* - * Simplified version of the above function. All parameters are the - * same, except that `scratch' and `backedges' are constructed - * internally. This is the simplest way to call the algorithm as a - * one-off; however, if you need to call it multiple times on the - * same network, it is probably better to call the above version - * directly so that you only construct `scratch' and `backedges' - * once. - * - * Additional return value is now -1, meaning that scratch space - * could not be allocated. - */ -int maxflow(int nv, int source, int sink, - int ne, const int *edges, const int *capacity, - int *flow, int *cut); - -#endif /* MAXFLOW_MAXFLOW_H */ |