Prims.cpp

#include <iostream>
using namespace std;

int minKey(int key[], bool mstSet[]) {
    int min = 99999, min_index;

    for (int v = 0; v < 5; v++)
        if (mstSet[v] == false && key[v] < min)
            min = key[v], min_index = v;

    return min_index;
}


void printMST(int parent[], int graph[5][5]) {
    cout << "Edge \tWeight\n";
    for (int i = 1; i < 5; i++)
        cout << parent[i] << " - " << i << " \t" << graph[i][parent[i]] << " \n";
}
void primMST(int graph[5][5]) {
    int parent[5];
    int key[5];
    bool mstSet[5];


    for (int i = 0; i < 5; i++)
        key[i] = 99999, mstSet[i] = false;
    key[0] = 0;
    parent[0] = -1;


    for (int count = 0; count < 5 - 1; count++) {
        int u = minKey(key, mstSet);


        mstSet[u] = true;

        for (int v = 0; v < 5; v++)
            if (graph[u][v] && mstSet[v] == false && graph[u][v] < key[v])
                parent[v] = u, key[v] = graph[u][v];
    }


    printMST(parent, graph);
}


int main() {

    int graph[5][5] = {{0, 2, 0, 6, 0},
                       {2, 0, 3, 8, 5},
                       {0, 3, 0, 0, 7},
                       {6, 8, 0, 0, 9},
                       {0, 5, 7, 9, 0}};

    primMST(graph);
}