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#include "../util.h"
struct edge {
ll from, to, id;
};
#define Edge edge
#include <graph/articulationPoints.cpp>
#undef Edge
#include <datastructures/unionFind.cpp>
vector<vector<int>> naiveBCC(int m) {
UnionFind uf(m);
vector<int> seen(ssize(adj), -1);
int run = 0;
for (int i = 0; i < ssize(adj); i++) {
for (auto e : adj[i]) {
run++;
seen[i] = run;
vector<ll> todo = {e.to};
seen[e.to] = run;
while (!todo.empty()) {
int c = todo.back();
todo.pop_back();
for (auto ee : adj[c]) {
if (seen[ee.to] == run) continue;
seen[ee.to] = run;
todo.push_back(ee.to);
}
}
for (auto ee : adj[i]) {
if (seen[ee.to] == run) uf.link(ee.id, e.id);
}
}
}
vector<vector<int>> res(m);
for (int i = 0; i < m; i++) {
res[uf.find(i)].push_back(i);
}
for (auto& v : res) ranges::sort(v);
res.erase(begin(ranges::remove_if(res, [](const vector<int>& v){return ssize(v) <= 1;})), end(res));
ranges::sort(res);
return res;
}
void stress_test_bcc() {
ll queries = 0;
for (int tries = 0; tries < 200'000; tries++) {
int n = Random::integer<int>(1, 30);
int m = Random::integer<int>(0, max<int>(1, min<int>(300, n*(n-1) / 2 + 1)));
Graph<NoData, 0, 1> g(n);
g.erdosRenyi(m);
adj.assign(n, {});
int nextId = 0;
g.forEdges([&](int a, int b){
adj[a].push_back({a, b, nextId});
adj[b].push_back({b, a, nextId});
nextId++;
});
auto expected = naiveBCC(nextId);
find();
vector<vector<int>> got(ssize(bcc));
for (int i = 0; i < ssize(bcc); i++) {
for (auto e : bcc[i]) got[i].push_back(e.id);
ranges::sort(got[i]);
}
ranges::sort(got);
if (got != expected) cerr << "error" << FAIL;
queries += n;
}
cerr << "tested random queries: " << queries << endl;
}
int main() {
stress_test_bcc();
}
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