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kruskal_algo.cpp

@@ -0,0 +1,151 @@
+//Kruskal Alogirthm
+/*Input:
+4 4
+
+0 1 3
+
+0 3 5
+
+1 2 1
+
+2 3 8
+
+Output:
+1 2 1
+
+0 1 3
+
+0 3 5*/
+#include <bits/stdc++.h>
+
+using namespace std;
+
+
+
+class Edge{
+
+public:
+
+    int src;
+
+    int dest;
+
+    int wt;
+
+};
+
+
+
+bool compare(Edge e1,Edge e2){
+
+    return e1.wt<e2.wt;
+
+}
+
+
+
+int getParent(int v,int parent[]){
+
+    if(parent[v]==v){
+
+        return v;
+
+    }
+
+    return getParent(parent[v],parent);
+
+}
+
+
+
+int main()
+
+{
+
+    int n,E;
+
+    cin>>n>>E;
+
+    Edge edges[E];
+
+    for(int i=0;i<E;i++){
+
+        cin>>edges[i].src>>edges[i].dest>>edges[i].wt;
+
+    }
+
+
+
+    //Kruskal algo
+
+
+
+    //sorted the edges array in increasing order
+
+    sort(edges,edges+E,compare);
+
+
+
+    Edge output[n-1];
+
+
+
+    //Union find algorithm to detect cycle
+
+    int parent[n];
+
+    for(int i=0;i<n;i++){
+
+        parent[i]=i;
+
+    }
+
+
+
+    int count=0;
+
+    int i=0;
+
+    while(count<n-1){
+
+        Edge currentEdge=edges[i];
+
+        int p1=getParent(currentEdge.src,parent);
+
+        int p2=getParent(currentEdge.dest,parent);
+
+        if(p1!=p2){
+
+            output[count]=currentEdge;
+
+            count++;
+
+            parent[p1]=p2;
+
+        }
+
+        i++;
+
+    }
+
+
+
+    //Printing the MST
+
+    for(int i=0;i<n-1;i++){
+
+        if(output[i].src<output[i].dest){
+
+            cout<<output[i].src<<" "<<output[i].dest<<" "<<output[i].wt<<endl;
+
+        }
+
+        else cout<<output[i].dest<<" "<<output[i].src<<" "<<output[i].wt<<endl;
+
+    }
+
+
+
+    return 0;
+
+}