Merge pull request #539 from ASHMITA-DE/master

Kruskal's Algorithm

Program's_Contributed_By_Contributors/C++_Programs/kruskals.cpp

@@ -0,0 +1,90 @@
+#include<bits/stdc++.h>
+using namespace std;
+int count1=0;
+class edge
+{
+	public:	int src,dest,cost;
+	edge(){}
+	edge(int s,int d,int c):src(s),dest(d),cost(c){}
+};
+bool operator < (const edge e1 , const edge e2)
+	{
+		return ((-1)*e1.cost)<((-1)*e2.cost);
+	}
+
+int findset(int a[],int e)
+{
+	while(a[e]!=-1)
+	{
+		e=a[e];
+	}
+	return e;
+}
+void set_union(int a[],int p,int q)
+{
+	a[p]=q;
+}
+int main()
+{
+	priority_queue<edge>q;
+	int v,e;
+	e=28; 
+	v=9;
+	int s[v];
+		cout<<"ENTER SRC,DEST,COST\n";
+	for(int i=0;i<v;i++)s[i]=-1;
+/*	for(int i=0;i<e;i++)
+	{
+	
+		int s,d,c;
+		cin>>s>>d>>c;
+		edge e(s,d,c);
+		q.push(e);		
+	}*/
+		int src[] = {0, 1, 0, 7, 1, 2, 1, 7, 2, 3, 2, 5, 2, 8, 3, 4, 3, 5, 4, 5, 5, 6, 6, 7, 6, 8, 7, 8};
+	int d[] = {1, 0, 7, 0, 2, 1, 7, 1, 3, 2, 5, 2, 8, 2, 4, 3, 5, 3, 5, 4, 6, 5, 7, 6, 8, 6, 8, 7};
+	int c[] = {4, 4, 8, 8, 8, 8, 11, 11, 7, 7, 4, 4, 2, 2, 9, 9, 14, 14, 10, 10, 2, 2, 1, 1, 6, 6, 7, 7};
+
+	//Edge *input = new Edge[E];
+	for(int i = 0;i<e;i++){
+       edge e(src[i],d[i],c[i]);
+       q.push(e);
+	}
+	vector<edge>res;
+	int mincost=0;
+	int cur=0;
+	edge *output = new edge[e];
+	while(!q.empty() && cur<v-1)
+	{	
+		edge e=q.top();
+		q.pop();
+		int sr=findset(s,e.src);
+		int d=findset(s,e.dest);
+		if(sr!=d)
+		{   output[cur] = e;
+		    count1++;
+			cur++;
+			mincost+=e.cost;
+			set_union(s,sr,d);
+			res.push_back(e);
+		}
+
+	}
+
+		cout << "Input to be used : " << endl;
+    cout << "Number of vertices: "<<v<<endl<<"Edges: ";
+
+
+		for(int i=0; i < v-1; i++){
+		if(output[i].src < output[i].dest)
+
+			cout<<output[i].src<<"-"<<output[i].dest<<", ";
+		else
+
+			cout<<output[i].dest<<"-"<<output[i].src<<", ";
+
+	}
+
+	cout<<endl<<"No. of steps = "<<count1;
+
+}