Example 1: kruskal's algorithm
#include<bits/stdc++.h>
using namespace std;
int main()
{
int n = 9;
int mat[9][9] = {
{100,4,100,100,100,100,100,8,100},
{4,100,8,100,100,100,100,100,100},
{100,8,100,7,100,4,100,100,2},
{100,100,7,100,9,14,100,100,100},
{100,100,100,9,100,10,100,100,100},
{100,100,4,14,10,100,2,100,100},
{100,100,100,100,100,2,100,1,6},
{8,100,100,100,100,100,1,100,7},
{100,100,2,100,100,100,6,7,100}};
int parent[n];
int edges[100][3];
int count = 0;
for(int i=0;i<n;i++)
for(int j=i;j<n;j++)
{
if(mat[i][j] != 100)
{
edges[count][0] = i;
edges[count][1] = j;
edges[count++][2] = mat[i][j];
}
}
for(int i=0;i<count-1;i++)
for(int j=0;j<count-i-1;j++)
if(edges[j][2] > edges[j+1][2])
{
int t1=edges[j][0], t2=edges[j][1], t3=edges[j][2];
edges[j][0] = edges[j+1][0];
edges[j][1] = edges[j+1][1];
edges[j][2] = edges[j+1][2];
edges[j+1][0] = t1;
edges[j+1][1] = t2;
edges[j+1][2] = t3;
}
int mst[n-1][2];
int mstVal = 0;
int l = 0;
cout<<endl;
for(int i=0;i<n;i++)
parent[i] = -1;
cout<<endl;
for(int i=0;i<count;i++)
{
if((parent[edges[i][0]] == -1 && parent[edges[i][1]] == -1))
{
parent[edges[i][0]] = edges[i][0];
parent[edges[i][1]] = edges[i][0];
mst[l][0] = edges[i][0];
mst[l++][1] = edges[i][1];
mstVal += edges[i][2];
}
else if((parent[edges[i][0]] == -1 && parent[edges[i][1]] != -1))
{
parent[edges[i][0]] = parent[edges[i][1]];
mst[l][0] = edges[i][1];
mst[l++][1] = edges[i][0];
mstVal += edges[i][2];
}
else if((parent[edges[i][0]] != -1 && parent[edges[i][1]] == -1))
{
parent[edges[i][1]] = parent[edges[i][0]];
mst[l][0] = edges[i][0];
mst[l++][1] = edges[i][1];
mstVal += edges[i][2];
}
else if(parent[edges[i][0]] != -1 && parent[edges[i][1]] != -1 && parent[edges[i][0]] != parent[edges[i][1]])
{
int p = parent[edges[i][1]];
for(int j=0;j<n;j++)
if(parent[j] == p)
parent[j] = parent[edges[i][0]];
mst[l][0] = edges[i][0];
mst[l++][1] = edges[i][1];
mstVal += edges[i][2];
}
}
for(int i=0;i<l;i++)
cout<<mst[i][0]<<" -> "<<mst[i][1]<<endl;
cout<<endl;
cout<<mstVal<<endl;
return(0);
}
Example 2: code implementation of krushkals algorithm
a,b,u,v,n,ne=1;
int min,mincost=0,cost[9][9],parent[9];
int find(int);
int uni(int,int);
void main()
{ #include <stdio.h>
#include <conio.h>
#include <stdlib.h>
int i,j,k,
printf("\n\tImplementation of Kruskal's Algorithm\n");
printf("\nEnter the no. of vertices:");
scanf("%d",&n);
printf("\nEnter the cost adjacency matrix:\n");
for(i=1;i<=n;i++)
{
for(j=1;j<=n;j++)
{
scanf("%d",&cost[i][j]);
if(cost[i][j]==0)
cost[i][j]=999;
}
}
printf("The edges of Minimum Cost Spanning Tree are\n");
while(ne < n)
{
for(i=1,min=999;i<=n;i++)
{
for(j=1;j <= n;j++)
{
if(cost[i][j] < min)
{
min=cost[i][j];
a=u=i;
b=v=j;
}
}
}
u=find(u);
v=find(v);
if(uni(u,v))
{
printf("%d edge (%d,%d) =%d\n",ne++,a,b,min);
mincost +=min;
}
cost[a][b]=cost[b][a]=999;
}
printf("\n\tMinimum cost = %d\n",mincost);
getch();
}
int find(int i)
{
while(parent[i])
i=parent[i];
return i;
}
int uni(int i,int j)
{
if(i!=j)
{
parent[j]=i;
return 1;
}
return 0;
}