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#include "../util.h"
#include <datastructures/unionFind.cpp>
#define Edge Edge_ // we have a struct named Edge in util.h
struct Edge {
int from, to;
ll cost;
bool operator<(const Edge& o) const {
return cost > o.cost;
}
};
#include <graph/kruskal.cpp>
ll prim(vector<Edge>& edges, int n) {
vector<vector<pair<ll, int>>> adj(n);
for (auto [a, b, d] : edges) {
adj[a].emplace_back(d, b);
adj[b].emplace_back(d, a);
}
priority_queue<pair<ll, int>> todo;
vector<bool> seen(n);
ll res = 0;
for (ll i = 0; i < n; i++) {
if (seen[i]) continue;
todo.push({0, i});
while (!todo.empty()) {
auto [d, c] = todo.top();
todo.pop();
if (seen[c]) continue;
seen[c] = true;
res += d;
for (auto e : adj[c]) {
todo.push(e);
}
}
}
return res;
}
void stress_test() {
ll queries = 0;
for (int tries = 0; tries < 100'000; tries++) {
int n = Random::integer<int>(2, 30);
int m = Random::integer<int>(0, max<int>(n, min<int>(500, n*(n-1) / 2 + 1)));
Graph<NoData> g(n);
g.erdosRenyi(m);
vector<Edge> edges;
g.forEdges([&](int a, int b){
ll w = Random::integer<ll>(-1'000'000'000ll, 1'000'000'000ll);
edges.push_back({a, b, w});
});
vector<Edge> mst;
ll got = kruskal(n, edges, mst);
ll expected = prim(edges, n);
if (got != expected) cerr << "got: " << got << ", expected: " << expected << FAIL;
queries += n;
}
cerr << "tested random queries: " << queries << endl;
}
constexpr int N = 500'000;
constexpr int M = 3'000'000;
void performance_test() {
timer t;
Graph<NoData> g(N);
g.erdosRenyi(M);
vector<Edge> edges;
g.forEdges([&](int a, int b){
ll w = Random::integer<ll>(-1'000'000'000ll, 1'000'000'000ll);
edges.push_back({a, b, w});
});
t.start();
vector<Edge> mst;
hash_t hash = kruskal(N, edges, mst);
t.stop();
if (t.time > 1000) cerr << "too slow: " << t.time << FAIL;
cerr << "tested performance: " << t.time << "ms (hash: " << hash << ")" << endl;
}
int main() {
stress_test();
performance_test();
}
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