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LaTeX-examples/presentations/ICPC-Referat/KruskalsAlgorithm.tex
2013-11-05 19:52:56 +01:00

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% Author: Martin Thoma
\subsection{Algorithmus von Kruskal}
\begin{frame}{Algorithmus von Kruskal}{Kruskal's algorithm}
$E$: Menge der ausgewählten Kanten, $S$: Menge der erreichbaren Knoten.\vspace{10pt}\pause
So lange, bis alle Knoten erreichbar sind:
Wähle Kante mit geringstem Gewicht
Wenn durch ausgewählte Kante ein Knoten erreichbar ist, der davor nicht in $S$ war, füge diese Kante zu $E$ und Knoten zu $E$ hinzu.
\end{frame}
\begin{frame}{Algorithmus von Kruskal}{Kruskal's algorithm}
\begin{figure}
\begin{tikzpicture}[scale=1.8, auto,swap]
% Draw a 7,11 network
% First we draw the vertices
\foreach \pos/\name in {{(0,2)/a}, {(2,1)/b}, {(4,1)/c},
{(0,0)/d}, {(3,0)/e}, {(2,-1)/f}, {(4,-1)/g}}
\node[vertex] (\name) at \pos {$\name$};
% Connect vertices with edges and draw weights
\foreach \source/ \dest /\weight in {b/a/7, c/b/8,d/a/5,d/b/9,
e/b/7, e/c/5,e/d/15,
f/d/6,f/e/8,
g/e/9,g/f/11}
\path[edge] (\source) -- node[weight] {$\weight$} (\dest);
% Start animating the vertex and edge selection.
\foreach \vertex / \fr in {d/1,a/1,e/2,c/2,f/3,b/4,g/10}
\path<\fr-> node[selected vertex] at (\vertex) {$\vertex$};
% For convenience we use a background layer to highlight edges
% This way we don't have to worry about the highlighting covering
% weight labels.
\begin{pgfonlayer}{background}
\pause
\foreach \source / \dest / \fr in {a/d/1,c/e/2,d/f/3,a/b/4,b/e/6,e/g/10}
\path<\fr->[selected edge] (\source.center) -- (\dest.center);
\foreach \source / \dest / \fr in {d/b/5,b/c/7,d/e/8,e/f/9,f/g/11}
\path<\fr->[ignored edge] (\source.center) -- (\dest.center);
\end{pgfonlayer}
\end{tikzpicture}
\end{figure}
\end{frame}
%% end of source
\begin{frame}[fragile]
\frametitle{Algorithmus von Kruskal}
\begin{lstlisting}
s is disjunct set of edges
n is number of edges in original graph
while s less than n - 1
e = smallest weight edge not deleted yet
// edge e = (u, v)
uset = s.find(u)
vset = s.find(v)
if (uset != vset)
edgesAccepted = edgesAccepted + 1
s.unionSets(uset, vset)
end if
end while
\end{lstlisting}
\end{frame}
\begin{frame}{Algorithmus von Kruskal}{Kruskal's algorithm}
Erfunden von:
1956: Joseph Kruskal
\begin{figure}
\includegraphics[scale=0.6]{Material/kruskal.jpg}
\caption{Kruskal}
\end{figure}
\end{frame}