#include
#include
#include
using namespace std;
#define edge pair
class Graph {
private:
vector G; // graph
vector T; // mst
int *parent;
int V; // number of vertices/nodes in graph
public:
Graph(int V);
void AddWeightedEdge(int u, int v, int w);
int find_set(int i);
void union_set(int u, int v);
void kruskal();
void print();
};
Graph::Graph(int V) {
parent = new int[V];
//i 0 1 2 3 4 5
//parent[i] 0 1 2 3 4 5
for (int i = 0; i < V; i++)
parent[i] = i;
G.clear();
T.clear();
}
void Graph::AddWeightedEdge(int u, int v, int w) {
G.push_back(make_pair(w, edge(u, v)));
}
int Graph::find_set(int i) {
// If i is the parent of itself
if (i == parent[i])
return i;
else
// Else if i is not the parent of itself
// Then i is not the representative of his set,
// so we recursively call Find on its parent
return find_set(parent[i]);
}
void Graph::union_set(int u, int v) {
parent[u] = parent[v];
}
void Graph::kruskal() {
int i, uRep, vRep;
sort(G.begin(), G.end()); // increasing weight
for (i = 0; i < G.size(); i++) {
uRep = find_set(G[i].second.first);
vRep = find_set(G[i].second.second);
if (uRep != vRep) {
T.push_back(G[i]); // add to tree
union_set(uRep, vRep);
}
}
}
void Graph::print() {
cout << "Edge :" << " Weight" << endl;
for (int i = 0; i < T.size(); i++) {
cout << T[i].second.first << " – " << T[i].second.second << " : "
<< T[i].first;
cout << endl;
}
}
int main() {
Graph g(6);
g.AddWeightedEdge(0, 1, 4);
g.AddWeightedEdge(0, 2, 4);
g.AddWeightedEdge(1, 2, 2);
g.AddWeightedEdge(1, 0, 4);
g.AddWeightedEdge(2, 0, 4);
g.AddWeightedEdge(2, 1, 2);
g.AddWeightedEdge(2, 3, 3);
g.AddWeightedEdge(2, 5, 2);
g.AddWeightedEdge(2, 4, 4);
g.AddWeightedEdge(3, 2, 3);
g.AddWeightedEdge(3, 4, 3);
g.AddWeightedEdge(4, 2, 4);
g.AddWeightedEdge(4, 3, 3);
g.AddWeightedEdge(5, 2, 2);
g.AddWeightedEdge(5, 4, 3);
g.kruskal();
g.print();
return 0;
}
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