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#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;
}