#include <stdio.h>
#include <stdbool.h>
#define V 3 // Number of vertices in the graph
// Function to find the vertex with the minimum key value
int minKey(int key[], bool mstSet[]) {
int min = INT_MAX, min_index;
for (int v = 0; v < V; v++) {
if (!mstSet[v] && key[v] < min) {
min = key[v];
min_index = v;
}
}
return min_index;
}
// Function to print the MST
void printMST(int parent[], int graph[V][V]) {
printf("Edge \tWeight\n");
for (int i = 1; i < V; i++) {
printf("%d - %d \t%d\n", parent[i], i, graph[i][parent[i]]);
}
}
// Function to implement Prim's algorithm
void primMST(int graph[V][V]) {
int parent[V]; // Array to store the MST
int key[V]; // Key values used to pick minimum weight edge
bool mstSet[V]; // To represent set of vertices included in MST
for (int i = 0; i < V; i++) {
key[i] = INT_MAX;
mstSet[i] = false;
}
key[0] = 0; // Make the first vertex as the starting vertex
parent[0] = -1; // First node is the root of the MST
for (int count = 0; count < V - 1; count++) {
int u = minKey(key, mstSet);
mstSet[u] = true;
for (int v = 0; v < V; v++) {
if (graph[u][v] && !mstSet[v] && graph[u][v] < key[v]) {
parent[v] = u;
key[v] = graph[u][v];
}
}
}
printMST(parent, graph);
}
int main() {
int graph[V][V] = {
{0, 3, 9},
{3, 0, 2},
{9, 2, 0}
};
primMST(graph);
return 0;
}