1 files changed, 49 insertions, 0 deletions
diff --git a/test/string/manacher.cpp b/test/string/manacher.cpp
new file mode 100644
index 0000000..503d181
--- /dev/null
+++ b/test/string/manacher.cpp
@@ -0,0 +1,49 @@
+#include "../util.h"
+#include <string/manacher.cpp>
+
+vector<int> naive(string_view s) {
+	vector<int> res(2 * sz(s) + 1);
+	for (int i = 0; i < sz(s); i++) { //odd palindromes
+		int j = 2*i+1;
+		while (i+res[j] < sz(s) && i-res[j] >= 0 && s[i-res[j]] == s[i+res[j]]) res[j]++;
+		res[j]*=2;
+		res[j]--;
+	}
+	for (int i = 0; i <= sz(s); i++) { //even palindromes
+		int j = 2*i;
+		while (i+res[j] < sz(s) && i-res[j]-1 >= 0 && s[i-res[j]-1] == s[i+res[j]]) res[j]++;
+		res[j] *= 2;
+	}
+	return res;
+}
+
+void stress_test() {
+	ll queries = 0;
+	for (int i = 0; i < 10'000; i++) {
+		int n = Random::integer<int>(1, 100);
+		auto s = Random::string(n, "abc");
+		vector<int> got = manacher(s);
+		vector<int> expected = naive(s);
+		if (got != expected) cerr << "error" << FAIL;
+		queries += n;
+	}
+	cerr << "tested random queries: " << queries << endl;
+}
+
+constexpr int N = 5'000'000;
+void performance_test() {
+	timer t;
+	auto s = Random::string(N, "a") + Random::string(N, "ab") + Random::string(N, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789$#");
+	t.start();
+	auto got = manacher(s);
+	t.stop();
+	hash_t hash = 0;
+	for (int x : got) hash += x;
+	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();
+}