vvii mst(int V, viii &E) {
vvii G(V);
union_find uf(V);
sort(E.begin(), E.end());
iter(it, E) {
int x = (*it).S.F;
int y = (*it).S.S;
if(uf.unite(x, y)) {
G[x].push_back(ii(y, (*it).F));
G[y].push_back(ii(x, (*it).F));
}
}
lld kruskal(lld idx) {
UnionFind UF(n);
vii MST; //Contiene las aristas del MST
sort(edges.begin(), edges.end());
lld mx = -INF;
for (lld i = idx; i < edges.size(); i++) {
lld w = edges[i].fst;
lld a = edges[i].snd.fst;
lld b = edges[i].snd.snd;
if (!UF.isSameSet(a, b)) {
MST.push_back(edges[i].snd);
mx = max(mx, w);
UF.Union(a, b);
}
}
//Existencia de MST:
return (UF.numSet() != 1) ? -1 : mx; // costo del MST
}
vii kruskal(viii &edges, int n, int m) {
vii ret;
UnionFind ds(n);
sort(edges.begin(), edges.end());
for (int i = 0; i < m; i++) {
int w = edges[i].st;
int u = edges[i].nd.st;
int v = edges[i].nd.nd;
if (ds._find(u) != ds._find(v)) {
ds._union(u, v);
ret.push_back({min(u, v), max(u, v)});
}
}
return ret;
}