Kruskal

#include <bits/stdc++.h>

using namespace std;

struct Edge
{
    int source, dest, cost;
};

Edge edge[100];
int par[100];
int g[100][100];

bool compare(const Edge &x, const Edge &y)
{
    return x.cost<y.cost;
}

int find (int v)
{
    if (par[v]==-1) return v;
    par[v] = find(par[v]);
    return par[v];
}

void merge (int v1, int v2)
{
    par[v1] = v2;
    return;
}

void Kruskal (int v, int e)
{
    int cnt=0, pos=1, source, dest, cost;
    Edge now;
    while(cnt<v-1)
    {
        if (pos>e) return;
        now = edge[pos++];
        source = now.source;
        dest = now.dest;
        cost=now.cost;
        int v1 = find(source);
        int v2 = find(dest);
        if(v1!=v2)
        {
            g[source][dest] = cost;
            merge(v1, v2);
            cnt++;
        }
    }
    return;
}

int main()
{
    int v,e;
    scanf("%d%d", &v, &e);
    int i, j;
    int source, dest, cost;
    for(i=0; i<=v; i++)
    {
        par[i]=-1;
    }
    for(i=0; i<e; i++)
    {
        scanf("%d%d%d", &source, &dest, &cost);
        edge[i].source = source;
        edge[i].dest = dest;
        edge[i].cost = cost;
    }
    memset(g, -1, sizeof(g));
    sort (edge, edge+e, compare);
    Kruskal(v, e);
    for(i=0; i<=v; i++)
    {
        for(j=0; j<=v; j++)
        {
            if(g[i][j]!=-1)
            {
                printf("Vertex %d and %d, cost %d\n", i, j, g[i][j]);
            }
        }
    }
    return 0;
}