Wednesday 20 August 2014

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C program to Implement Dijkstra Algorithm

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C Program to implement Dijkstra’s algorithm. Dijkstra’s Algorithm finds the shortest path with the lower cost in a Graph. Dijkstra’s Algorithm solves the Single Source Shortest Path problem for a Graph. It is a Greedy algorithm and similar to Prim’s algorithm.

C program to Implement Dijkstra Algorithm

#include <stdio.h>
#include <conio.h>
#define infinity 999
 
void dij(int n,int v,int cost[10][10],int dist[])
{
	int i,u,count,w,flag[10],min;
	for(i=1;i<=n;i++)
	flag[i]=0,dist[i]=cost[v][i];
	count=2;
	while(count<=n)
	{
		min=99;
		for(w=1;w<=n;w++)
		if(dist[w]<min && !flag[w])
		min=dist[w],u=w;
		flag[u]=1;
		count++;
		for(w=1;w<=n;w++)
		if((dist[u]+cost[u][w]<dist[w]) && !flag[w])
		dist[w]=dist[u]+cost[u][w];
	}
}
 
void main()
{
	int n,v,i,j,cost[10][10],dist[10];
	clrscr();
	printf("n Enter the number of nodes:");
	scanf("%d",&n);
	printf("n Enter the cost matrix:n");
	for(i=1;i<=n;i++)
	for(j=1;j<=n;j++)
	{	
		scanf("%d",&cost[i][j]);
		if(cost[i][j]==0)
		cost[i][j]=infinity;
	}	
	printf("n Enter the source matrix:");
	scanf("%d",&v);
	dij(n,v,cost,dist);
	printf("n Shortest path:n");
	for(i=1;i<=n;i++)
	if(i!=v)
	printf("%d->%d,cost=%dn",v,i,dist[i]);
	getch();
}