1 files changed, 85 insertions, 0 deletions
diff --git a/test/string/kmp.cpp b/test/string/kmp.cpp
new file mode 100644
index 0000000..9c9c924
--- /dev/null
+++ b/test/string/kmp.cpp
@@ -0,0 +1,85 @@
+#include "../util.h"
+#include <string/kmp.cpp>
+
+vector<int> naive(string_view s) {
+	vector<int> res(sz(s) + 1, -1);
+	for (int i = 0; i < sz(s); i++) {
+		for (int j = 0; j <= i; j++)
+			if (s.substr(0, j) == s.substr(i-j+1, j))
+				res[i+1] = j;
+	}
+	return res;
+}
+
+void stress_test_preprocessing() {
+	ll queries = 0;
+	for (int tries = 0; tries < 100'000; tries++) {
+		int n = Random::integer<int>(1, 15);
+		auto s = Random::string(n, "abc");
+		auto got = kmpPreprocessing(s);
+		auto expected = naive(s);
+		if (got != expected) cerr << "  error" << FAIL;
+		queries += n;
+	}
+	cerr << "  tested random queries: " << queries << endl;
+}
+
+constexpr int N = 10'000'000;
+void performance_test_preprocessing() {
+	timer t;
+	auto s = Random::string(N, "a") + Random::string(N, "ab") + Random::string(N, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789$#");
+	t.start();
+	auto res = kmpPreprocessing(s);
+	t.stop();
+	hash_t hash = 0;
+	for (int x : res) hash += x;
+	if (t.time > 500) cerr << "  too slow: " << t.time << FAIL;
+	cerr << "  tested performance: " << t.time << "ms (hash: " << hash << ")" << endl;
+}
+
+vector<int> naive(string_view s, string_view sub) {
+	vector<int> res;
+	auto pos = s.find(sub);
+	while (pos != string_view::npos) {
+		res.push_back(pos);
+		pos = s.find(sub, pos + 1);
+	}
+	return res;
+}
+
+void stress_test_kmp() {
+	ll queries = 0;
+	auto a = Random::string(10'000, "abc");
+	for (int tries = 0; tries < 10'000; tries++) {
+		int n = Random::integer<int>(1, 10);
+		auto b = Random::string(n, "abc");
+		auto got = kmpSearch(a, b);
+		auto expected = naive(a, b);
+		if (got != expected) cerr << "  error" << FAIL;
+		queries += got.size();
+	}
+	cerr << "  tested random queries: " << queries << endl;
+}
+
+void performance_test_kmp() {
+	timer t;
+	auto s = Random::string(N, "a") + Random::string(N, "ab") + Random::string(N, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789$#");
+	auto sub1 = Random::string(N/2, "a");
+	auto sub2 = Random::string(N/2, "ab");
+	hash_t hash = 0;
+	t.start();
+	hash += kmpSearch(s, sub1).size();
+	hash += kmpSearch(s, sub2).size();
+	t.stop();
+	if (t.time > 500) cerr << "  too slow: " << t.time << FAIL;
+	cerr << "  tested performance: " << t.time << "ms (hash: " << hash << ")" << endl;
+}
+
+int main() {
+	cerr << "preprocessing:" << endl;
+	stress_test_preprocessing();
+	performance_test_preprocessing();
+	cerr << "kmp:" << endl;
+	stress_test_kmp();
+	performance_test_kmp();
+}