Merge pull request #2524 from abhaysaini/patch-2

Create Kruskal's ALgorithm.cpp

Program's_Contributed_By_Contributors/C++/Kruskal's ALgorithm.cpp

@@ -0,0 +1,82 @@
+#include <bits/stdc++.h>
+using namespace std;
+struct Node
+{
+    int u;
+    int v;
+    int weight;
+    Node(int first, int second, int wt)
+    {
+        u = first;
+        v = second;
+        weight = wt;
+    }
+};
+bool cmp(Node a, Node b)
+{
+    return a.weight < b.weight;
+}
+
+int findPar(int u, vector<int> &parent)
+{
+    if (u == parent[u])
+        return u;
+    return parent[u] = findPar(parent[u], parent);
+}
+
+void unionn(int u, int v, vector<int> &parent, vector<int> &rank)
+{
+    u = findPar(u, parent);
+    v = findPar(v, parent);
+    if (rank[u] < rank[v])
+    {
+        parent[u] = v;
+    }
+    else if (rank[v] < rank[u])
+    {
+        parent[v] = u;
+    }
+    else
+    {
+        parent[v] = u;
+        rank[u]++;
+    }
+}
+
+int main()
+{
+    int n, m;
+    cin >> n >> m;
+    vector<Node> v;
+    for (int i = 0; i < m; i++)
+    {
+        int x, y, w;
+        cin >> x >> y >> w;
+        v.push_back(Node(x, y, w));
+    }
+    sort(v.begin(), v.end(), cmp);
+    vector<int> parent(n, 0), rank(n, 0);
+    for (int i = 0; i < n; i++)
+    {
+        parent[i] = i;
+    }
+
+    int cost = 0;
+    vector<pair<int,int>> mst;
+
+    for (auto it : v)
+    {
+        if (findPar(it.v, parent) != findPar(it.u, parent))
+        {
+            cost += it.weight;
+            mst.push_back({it.u, it.v});
+            unionn(it.u, it.v, parent, rank);
+        }
+    }
+    cout << cost << endl;
+    for (auto it : mst)
+    {
+        cout << it.first << " - " << it.second << endl;
+    }
+    return 0;
+}