#include <stdio.h>
#include <limits.h>
// Number of vertices in the graph
#define V 9
// A utility function to find the vertex with minimum distance value, from
// the set of vertices not yet included in shortest path tree
int minDistance(int dist[], int sptSet[]) {
// Initialize min value
int min = INT_MAX, min_index;
int v;
for (v = 0; v < V; v++)
if (sptSet[v] == 0 && dist[v] <= min)
min = dist[v], min_index = v;
return min_index;
}
// A utility function to print the constructed distance array
void printSolution(int dist[], int n) {
printf("Vertex Distance from Source\n");
int i;
for (i = 0; i < V; i++)
printf("%d \t\t %d\n", i, dist[i]);
}
// Funtion that implements Dijkstra's single source shortest path algorithm
// for a graph represented using adjacency matrix representation
void dijkstra(int graph[V][V], int src) {
int dist[V]; // The output array. dist[i] will hold the shortest
// distance from src to i
int sptSet[V]; // sptSet[i] will 1 if vertex i is included in shortest
// path tree or shortest distance from src to i is finalized
// Initialize all distances as INFINITE and stpSet[] as 0
int i, count, v;
for (i = 0; i < V; i++)
dist[i] = INT_MAX, sptSet[i] = 0;
// Distance of source vertex from itself is always 0
dist[src] = 0;
// Find shortest path for all vertices
for (count = 0; count < V - 1; count++) {
// Pick the minimum distance vertex from the set of vertices not
// yet processed. u is always equal to src in first iteration.
int u = minDistance(dist, sptSet);
// Mark the picked vertex as processed
sptSet[u] = 1;
// Update dist value of the adjacent vertices of the picked vertex.
for (v = 0; v < V; v++)
// Update dist[v] only if is not in sptSet, there is an edge from
// u to v, and total weight of path from src to v through u is
// smaller than current value of dist[v]
if (!sptSet[v] && graph[u][v] && dist[u] != INT_MAX && dist[u]
+ graph[u][v] < dist[v])
dist[v] = dist[u] + graph[u][v];
}
// print the constructed distance array
printSolution(dist, V);
}
// driver program to test above function
int main() {
/* Let us create the example graph discussed above */
int graph[V][V] = {{0, 2, 0, 0, 0, 0, 0, 5, 0},
{5, 0, 9, 0, 0, 0, 0, 11, 0},
{0, 2, 0, 7, 0, 4, 0, 0, 2},
{0, 0, 1, 0, 9, 14, 0, 0, 0},
{0, 0, 0, 4, 0, 10, 0, 0, 0},
{0, 0, 2, 0, 10, 0, 2, 0, 0},
{0, 0, 0, 1, 0, 2, 0, 1, 6},
{9, 11, 0, 0, 0, 0, 1, 0, 7},
{0, 0, 1, 0, 0, 0, 6, 7, 0}
};
dijkstra(graph, 0);
return 0;
}
Output
Vertex Distance from Source
0 0
1 2
2 8
3 7
4 16
5 8
6 6
7 5
8 10
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