1 files changed, 62 insertions, 0 deletions
diff --git a/test/string/suffixAutomaton.cpp b/test/string/suffixAutomaton.cpp
new file mode 100644
index 0000000..c2ff511
--- /dev/null
+++ b/test/string/suffixAutomaton.cpp
@@ -0,0 +1,62 @@
+#include "../util.h"
+#include <string/suffixAutomaton.cpp>
+
+pair<int, int> naive(string_view s, string_view t) {
+	int pos = 0;
+	int len = 0;
+	for (int j = 0; j < sz(t); j++) {
+		for (int i = 0; i < sz(s); i++) {
+			int cur = 0;
+			while (i+cur < sz(s) && j+cur < sz(t) && s[i+cur] == t[j+cur]) cur++;
+			if (cur > len) {
+				pos = j;
+				len = cur;
+			}
+		}
+	}
+	return {pos, len};
+}
+
+void stress_test() {
+	ll queries = 0;
+	for (int i = 0; i < 1000; i++) {
+		int n = Random::integer<int>(1, 100);
+		auto s = Random::string(n, "abc");
+		SuffixAutomaton sa(s);
+		for (int j = 0; j < 1000; j++) {
+			int m = Random::integer<int>(1, 100);
+			auto t = Random::string(m, "abc");
+			auto got = sa.longestCommonSubstring(t);
+			auto expected = naive(s, t);
+			if (got != expected) cerr << "error" << FAIL;
+			queries += m;
+		}
+	}
+	cerr << "tested random queries: " << queries << endl;
+}
+
+constexpr int N = 500'000;
+void performance_test() {
+	timer t;
+	auto s = Random::string(N, "a") + Random::string(N, "ab") + Random::string(N, "abcdefghijklmnopqrstuvwxyz");
+	t.start();
+	SuffixAutomaton sa(s);
+	t.stop();
+	hash_t hash = 0;
+	for (ll c = 0; c < sz(s);) {
+		int m = Random::integer<int>(1, 1000);
+		s = Random::string(m, "abc");
+		t.start();
+		auto [p, l] = sa.longestCommonSubstring(s);
+		t.stop();
+		hash += l + p;
+		c += m;
+	}
+	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();
+}