How do I implement Dijkstra's algorithm in C?

How do I implement Dijkstra's algorithm in C?

To implement Dijkstra's algorithm in C, you'll need to use a priority queue to efficiently select the next vertex. Do you have a specific graph representation in mind?

I was thinking of using an adjacency matrix.

Great choice! You can represent your graph as a 2D array. Initialize distances and a visited array. Would you like a code snippet?

Yes, please! That would be really helpful.

Here's a simple implementation:

#include <stdio.h>
#include <limits.h>
#define V 5

int minDistance(int dist[], int sptSet[]) {
    int min = INT_MAX, min_index;
    for (int v = 0; v < V; v++) {
        if (sptSet[v] == 0 && dist[v] <= min) {
            min = dist[v];
            min_index = v;
        }
    }
    return min_index;
}

void dijkstra(int graph[V][V], int src) {
    int dist[V];
    int sptSet[V];
    for (int i = 0; i < V; i++) {
        dist[i] = INT_MAX;
        sptSet[i] = 0;
    }
    dist[src] = 0;
    for (int count = 0; count < V - 1; count++) {
        int u = minDistance(dist, sptSet);
        sptSet[u] = 1;
        for (int v = 0; v < V; 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 distance array
}

Let me know if you need further explanation!

This is perfect! Can you explain how the priority queue works in this context?