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Dijkistra Shortest Path

kkarnez
kkarnez asked
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Last Modified: 2006-11-17
Hi guys
Does anyone has the source for Dijkistra's 'Shortest Path' algorithm?
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Finding the Shortest Path in a dense graph??

I'll post it if you swear this is not a homework ;)

-julio

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Commented:
Of course...
Commented:
From "design and analysis of algorithms" - Jeff Smith

/* given a set of n vertices, a source vertex v and an nx n cost array c, this algorithm returns the cost fo the cheapest path from v to every other vertex. The vertices are index from 1 to n: T[i] is true iff the vertex i is included in T */
SingleSource( n,v,c)
for( i=1 to n) {
cost[i] = c[v,i]; /* initialise cost matrix */
T[v] = false; /* T is initially empty */
}
T[v] = true; /* include source vertex in T */
newest = v; /* newest node used to update cost */
for( i = 2 to n) { /* choose the ith vertex of T and see */
leastcost = INFINITY /* if inclusion of the latest */
for( j=1 to n) { /* node in T allows cheaper access */
if( !T[j] ) { /* to any node not in T */
if( cost[newest] + c[newest,j] < cost[j]) {
cost[j] = cost[newest] + c[newest,j];
} /* endif */ /* kind of useless if i = 2 */
if( cost[j] < leastcost) { /*and keep track of */
cheapest = j; /* the vertex not in T */
leascost = cost[j]; /* with the lowest access */
} /* endif */
} /* endif *
T[cheapest] = true; /* include this vertex in T */
newest = cheapest /* and record it as the */
} /* end for */ /* newest vertex */
} /* end for */
return (cost);

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