merge mzuenni changes

1 files changed, 59 insertions, 0 deletions

diff --git a/test/graph/reroot.cpp b/test/graph/reroot.cpp
new file mode 100644
index 0000000..d5043b4
--- /dev/null
+++ b/test/graph/reroot.cpp
@@ -0,0 +1,59 @@
+#include "../util.h"
+#include <graph/reroot.cpp>
+
+void stress_test() {
+	for (int tries = 0; tries < 50'000; tries++) {
+		int n = Random::integer<int>(1, 50);
+		Graph<NoData> g(n);
+		g.tree();
+
+        adj.assign(n, {});
+		g.forEdges([&](int a, int b){
+			adj[a].emplace_back(b, Random::integer(0, 10));
+			adj[b].emplace_back(a, Random::integer(0, 10));
+		});
+
+        Reroot re;
+        auto ans = re.solve();
+
+        auto dfs = [&](auto& self, int u, int p) -> ll {
+            ll val = 0;
+            for (auto [v, w] : adj[u]) if (v != p) {
+                val ^= ((v ^ u) + self(self, v, u)) * w % MOD;
+            }
+            return u ^ val;
+        };
+        for (int i=0; i<n; i++) {
+            if (ans[i] != dfs(dfs, i, -1)) {
+                cerr << "WA expected " << dfs(dfs, i, -1) << " got " << ans[i] << FAIL;
+            }
+        }
+	}
+	cerr << "tested random 50'000 tests" << endl;
+}
+
+constexpr int N = 1'000'000;
+void performance_test() {
+	timer t;
+	Graph<NoData> g(N);
+	g.tree();
+    adj.assign(N, {});
+	g.forEdges([&](int a, int b){
+        adj[a].emplace_back(b, Random::integer(0, (int)1e9));
+        adj[b].emplace_back(a, Random::integer(0, (int)1e9));
+	});
+
+    ll hash = 0;
+	t.start();
+    Reroot re;
+    auto ans = re.solve();
+    hash = accumulate(all(ans), 0LL);
+	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();
+}