1 files changed, 61 insertions, 0 deletions
diff --git a/test/string/suffixArray.cpp b/test/string/suffixArray.cpp
new file mode 100644
index 0000000..4945d8e
--- /dev/null
+++ b/test/string/suffixArray.cpp
@@ -0,0 +1,61 @@
+#include "../util.h"
+#include <string/suffixArray.cpp>
+
+vector<int> naive(string_view s) {
+	vector<int> SA(sz(s));
+	iota(all(SA), 0);
+	sort(all(SA), [s](int a, int b){
+		return s.substr(a) < s.substr(b);
+	});
+	return SA;
+}
+
+int lcp(string_view s, int x, int y) {
+	int res = 0;
+	while (x + res < sz(s) && y + res < sz(s) && s[x + res] == s[y + res]) res++;
+	return res;
+}
+
+void stress_test() {
+	ll queries = 0;
+	for (int i = 0; i < 100; i++) {
+		int n = Random::integer<int>(1, 100);
+		auto s = Random::string(n, "abc");
+		SuffixArray sa(s);
+		vector<int> got = sa.SA;
+		vector<int> expected = naive(s);
+		vector<int> SA(n);
+		if (got != expected) cerr << "error: SA" << FAIL;
+		got = sa.LCP;
+		swap(SA, expected);
+		for (int x = 0; x < n; x++) {
+			for (int y = 0; y < n; y++) {
+				int gotLCP = sa.lcp(x, y);
+				int expectedLCP = lcp(s, x, y);
+				if (gotLCP != expectedLCP) cerr << "error: lcp" << FAIL;
+			}
+			if (x > 0) expected[x] = lcp(s, SA[x-1], SA[x]);
+		}
+		if (got != expected) cerr << "error: LCP" << FAIL;
+		queries += n;
+	}
+	cerr << "tested random queries: " << queries << endl;
+}
+
+constexpr int N = 200'000;
+void performance_test() {
+	timer t;
+	auto s = Random::string(N, "a") + Random::string(N, "ab") + Random::string(N, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789$#");
+	t.start();
+	SuffixArray sa(s);
+	t.stop();
+	hash_t hash = 0;
+	for (int i = 0; i < sz(sa.SA); i++) hash += i*sa.SA[i];
+	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();
+}