http://in.docsity.com/en-docs/Kruskals_Algorithm_-_C_plus_plus_Code

// kruskal minimum spanning tree
#include
#include

//structure for graph

struct str{
int edge,n1,n2;
}s0[20],s1[20];

//structure for checking nodes

struct st{
int val,flag;
}s2[20];

void input();
void filter();
void sort();
void min();
void update(int,int,int);

int n,e,cnt=0,Tcost=0;
int link[10][10];

void main()
{
clrscr();
input();
cout<<"this is filtered output\n";
filter();
cout<<"this is sorted output\n";
sort();
min();
cout<<"\nTcost is "<<Tcost;
getch();
}

void input()
{
cout<>n>>e;
cout<<"enter input for upper triangle matrix\n";
for(int i=0;i<n;i++)
{
for(int j=0;ji)
{
cout<<"enter link of node "<<i<<" to node "<<j<>link[i][j];
}
else
{
if(i==j)
link[i][j]=0;
else
link[i][j]=link[j][i];
}
}
}
}

int k=0,count=0;

void filter()
{
for(int i=0;i<n;i++)
{
for(int j=0;j<n;j++)
{
if(link[i][j]!=0)
{
s0[k].edge=link[i][j];
s0[k].n1=i;
s0[k].n2=j;
k++;
count++;
}
}
}
i=0;
int j=0;
int flag=1;
for(int l=0;l<count;l++)
{
if(i==0)
{
s1[j].edge=s0[i].edge;
s1[j].n1=s0[i].n1;
s1[j].n2=s0[i].n2;
i++;
j++;
}
else
{
k=0;
while(k<j)
{
if(s1[k].edge==s0[i].edge && s1[k].n1==s0[i].n2 && s1[k].n2==s0[i].n1)
{
flag=0;
break;
}
else
k++;
}
if(flag)
{
s1[j].edge=s0[i].edge;
s1[j].n1=s0[i].n1;
s1[j].n2=s0[i].n2;
i++;
j++;
cnt++;
}
else
{
i++;
flag=1;
}
}
}
for(i=0;i<=cnt;i++)
cout<<s1[i].edge<<"\t"<<s1[i].n1<<"\t"<<s1[i].n2<<"\n"<<endl;
}

void sort()
{
for(int i=0;i<=cnt-1;i++)
{
for(int j=0;js1[j+1].edge)
{
int t=s1[j].edge;
s1[j].edge=s1[j+1].edge;
s1[j+1].edge=t;

int t1=s1[j].n1;
s1[j].n1=s1[j+1].n1;
s1[j+1].n1=t1;

int t2=s1[j].n2;
s1[j].n2=s1[j+1].n2;
s1[j+1].n2=t2;
}
}
}
for(i=0;i<=cnt;i++)
cout<<s1[i].edge<<"\t"<<s1[i].n1<<"\t"<<s1[i].n2<<endl;

}

void min()
{

//initialize s2 structure

for(int i=0;i<n;i++)
{
s2[i].val=i;
s2[i].flag=i+1;
}

int u,v,y,z;
int cur=n;

for(i=0;i<e;i++)
{
y=s1[i].n1;
z=s1[i].n2;
//cout<<"y & z "<<y<<z;
u=s2[y].flag;
v=s2[z].flag;
if(u!=v){
Tcost+=s1[i].edge;
cout<<"\nedge "<<y<“<<z;
}
cur=cur+1;
update(y,z,cur);
}
}

void update(int y,int z,int cur)
{
for(int i=0;i<n;i++)
{
if(i!=y)
{
if(s2[y].flag==s2[i].flag)
s2[i].flag=cur;
}

if(i!=z)
{
if(s2[z].flag==s2[i].flag)
s2[i].flag=cur;
}
}
s2[y].flag=cur;
s2[z].flag=cur;
}