1 files changed, 55 insertions, 0 deletions
diff --git a/test/string/longestCommonSubsequence.cpp b/test/string/longestCommonSubsequence.cpp
new file mode 100644
index 0000000..6d7a6c5
--- /dev/null
+++ b/test/string/longestCommonSubsequence.cpp
@@ -0,0 +1,55 @@
+#include "../util.h"
+#include <string/longestCommonSubsequence.cpp>
+
+bool isSubstr(string_view s, string_view sub) {
+	int i = 0;
+	for (char c : s) {
+		if (i < sz(sub) && c == sub[i]) i++;
+	}
+	return i >= sz(sub);
+}
+
+string naive(string_view s, string_view t) {
+	string res = "";
+	for (ll i = 1; i < (1ll << sz(s)); i++) {
+		string tmp;
+		for (ll j = 0; j < sz(s); j++) {
+			if (((i >> j) & 1) != 0) tmp.push_back(s[j]);
+		}
+		if (sz(tmp) >= sz(res) && isSubstr(t, tmp)) res = tmp;
+	}
+	return res;
+}
+
+void stress_test() {
+	ll queries = 0;
+	for (ll i = 0; i < 10'000; i++) {
+		int n = Random::integer<int>(1, 12);
+		int m = Random::integer<int>(1, 12);
+		auto s = Random::string(n, "abc");
+		auto t = Random::string(m, "abc");
+		auto got = lcss(s, t);
+		auto expected = naive(s, t);
+		if (got != expected) cerr << s << ", " << t << ", got: " << got << ", expected: " << expected << FAIL;
+		queries += n + m;
+	}
+	cerr << "tested random queries: " << queries << endl;
+}
+
+constexpr int N = 2'000;
+void performance_test() {
+	timer t;
+	auto a = Random::string(N, "a") + Random::string(N, "ab") + Random::string(N, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789$#");
+	auto b = Random::string(N, "a") + Random::string(N, "ab") + Random::string(N, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789$#");
+	t.start();
+	auto res = lcss(a, b);
+	t.stop();
+	hash_t hash = sz(res);
+	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();
+}