Kruskal's Minimum Spanning Tree

kruskalMST.cpp

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+#include <bits/stdc++.h>
+using namespace std;
+
+struct edge
+{
+    int u;
+    int v;
+    int w;
+};
+
+struct point
+{
+    int parent;
+    int rank;
+};
+
+int comp(edge a, edge b)
+{
+    if (a.w == b.w)
+        return a.v < b.v;
+    return a.w < b.w;
+}
+
+int find(point subset[], int node)
+{
+    if (subset[node].parent == -1)
+        return node;
+    return subset[node].parent = find(subset, subset[node].parent);
+}
+
+void unionFun(point subset[], int xroot, int yroot)
+{
+    if (subset[yroot].rank >= subset[xroot].rank)
+    {
+        subset[xroot].parent = yroot;
+        subset[yroot].rank += subset[xroot].rank;
+    }
+    else
+    {
+        subset[yroot].parent = xroot;
+        subset[xroot].rank += subset[yroot].rank;
+    }
+}
+
+void kruskalMST(vector<edge> graph, int V, int E)
+{
+    sort(graph.begin(), graph.end(), comp);
+    point subset[V];
+    int cost = 0;
+
+    for (int i = 0; i < V; i++)
+    {
+        subset[i].parent = -1;
+        subset[i].rank = 1;
+    }
+
+    int cnt = 0;
+    vector<edge> ans;
+    for (int i = 0; cnt < V - 1, i < E; i++)
+    {
+        edge node = graph[i];
+        int u = node.u;
+        int v = node.v;
+        int w = node.w;
+
+        int xroot = find(subset, u);
+        int yroot = find(subset, v);
+
+        if (xroot != yroot)
+        {
+            cost += w;
+            ans.push_back(node);
+            unionFun(subset, xroot, yroot);
+        }
+    }
+    cout << cost << endl;
+    for (int i = 0; i < ans.size(); i++)
+    {
+        cout << ans[i].u << " " << ans[i].v << " " << ans[i].w << endl;
+    }
+}
+
+int main()
+{
+    int V = 4;
+    int E = 5;
+
+    vector<edge> graph;
+    graph.push_back({0, 1, 10});
+    graph.push_back({0, 2, 6});
+    graph.push_back({0, 3, 5});
+    graph.push_back({1, 3, 15});
+    graph.push_back({2, 3, 4});
+
+    kruskalMST(graph, V, E);
+    return 0;
+}