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-rw-r--r--graph/articulationPoints.cpp47
-rw-r--r--graph/graph.tex3
2 files changed, 50 insertions, 0 deletions
diff --git a/graph/articulationPoints.cpp b/graph/articulationPoints.cpp
new file mode 100644
index 0000000..b99a286
--- /dev/null
+++ b/graph/articulationPoints.cpp
@@ -0,0 +1,47 @@
+vector< vector<int> > adjlist;
+vector<int> low;
+vector<int> d;
+vector<bool> isArtPoint;
+vector< vector<int> > bridges; //nur fuer Bruecken
+int counter = 0;
+
+void visit(int v, int parent) {
+ d[v] = low[v] = ++counter;
+ int numVisits = 0, maxlow = 0;
+
+ for (vector<int>::iterator vit = adjlist[v].begin(); vit != adjlist[v].end(); vit++) {
+ if (d[*vit] == 0) {
+ numVisits++;
+ visit(*vit, v);
+ if (low[*vit] > maxlow) {
+ maxlow = low[*vit];
+ }
+
+ if (low[*vit] > d[v]) { //nur fuer Bruecken
+ bridges[v].push_back(*vit); bridges[*vit].push_back(v);
+ }
+
+ low[v] = min(low[v], low[*vit]);
+ } else {
+ if (d[*vit] < low[v]) {
+ low[v] = d[*vit];
+ }
+ }
+ }
+
+ if (parent == -1) {
+ if (numVisits > 1) isArtPoint[v] = true;
+ } else {
+ if (maxlow >= d[v]) isArtPoint[v] = true;
+ }
+}
+
+void findArticulationPoints() {
+ low.clear(); low.resize(adjlist.size());
+ d.clear(); d.assign(adjlist.size(), 0);
+ isArtPoint.clear(); isArtPoint.assign(adjlist.size(), false);
+ bridges.clear(); isBridge.resize(adjlist.size()); //nur fuer Bruecken
+ for (int v = 0; v < (int)adjlist.size(); v++) {
+ if (d[v] == 0) visit(v, -1);
+ }
+} \ No newline at end of file
diff --git a/graph/graph.tex b/graph/graph.tex
index 2bf395c..5fc725e 100644
--- a/graph/graph.tex
+++ b/graph/graph.tex
@@ -13,5 +13,8 @@ Kürzestes Pfade in Graphen mit negativen Kanten. Erkennt negative Zyklen.
\subsection{Strongly Connected Components (\textsc{Tarjans}-Algorithmus)}
\lstinputlisting{graph/scc.cpp}
+\subsection{Artikulationspunkte und Brücken}
+\lstinputlisting{graph/articulationPoints.cpp}
+
\subsection{Max-Flow (\textsc{Edmonds-Karp}-Algorithmus)}
\lstinputlisting{graph/edmondsKarp.cpp} \ No newline at end of file