1 files changed, 58 insertions, 0 deletions
diff --git a/test/datastructures/fenwickTree.cpp b/test/datastructures/fenwickTree.cpp
new file mode 100644
index 0000000..c1ef6bf
--- /dev/null
+++ b/test/datastructures/fenwickTree.cpp
@@ -0,0 +1,58 @@
+#include "../util.h"
+#include <datastructures/fenwickTree.cpp>
+
+//void update(int i, ll val)
+//void init(int n)
+//prefix_sum(int i)
+
+void stress_test() {
+	ll queries = 0;
+	for (int tries = 0; tries < 100; tries++) {
+		int n = Random::integer<int>(10, 100);
+		init(n);
+		vector<ll> naive(n);
+		for (int operations = 0; operations < 1000; operations++) {
+			{
+				int i = Random::integer<int>(0, n);
+				ll x = Random::integer<ll>(-1000, 1000);
+				update(i, x);
+				naive[i] += x;
+			}
+			{
+				queries++;
+				int i = Random::integer<int>(0, n);
+				ll got = prefix_sum(i);
+				ll expected = 0;
+				for (int j = 0; j <= i; j++) expected += naive[j];
+				if (got != expected) cerr << "got: " << got << ", expected: " << expected << FAIL;
+			}
+		}
+	}
+	cerr << "tested random queries: " << queries << endl;
+}
+
+constexpr int N = 1'000'000;
+void performance_test() {
+	timer t;
+	t.start();
+	init(N);
+	t.stop();
+	hash_t hash = 0;
+	for (int operations = 0; operations < N; operations++) {
+		int i = Random::integer<int>(0, N);
+		int j = Random::integer<int>(0, N);
+		ll x = Random::integer<ll>(-1000, 1000);
+		
+		t.start();
+		update(i, x);
+		hash ^= prefix_sum(j);
+		t.stop();
+	}
+	if (t.time > 500) cerr << "too slow: " << t.time << FAIL;
+	cerr << "tested performance: " << t.time << "ms (hash: " << hash << ")" << endl;
+}
+
+int main() {
+	stress_test();
+	performance_test();
+}