feat: Add matrix product test implementation for NMatrix using modint

Author: weilycoder

test/matrix_product.test.cpp

@@ -0,0 +1,27 @@
+#define PROBLEM "https://judge.yosupo.jp/problem/matrix_product"
+
+#include "../weilycoder/matrix.hpp"
+#include "../weilycoder/number_theory/modint.hpp"
+#include <cstdint>
+#include <iostream>
+using namespace std;
+using namespace weilycoder;
+
+int main() {
+  cin.tie(nullptr)->sync_with_stdio(false);
+  cin.exceptions(cin.failbit | cin.badbit);
+  size_t N, M, K;
+  cin >> N >> M >> K;
+  NMatrix<modint<998244353>> A(N, M), B(M, K);
+  for (size_t i = 0; i < N; ++i)
+    for (size_t j = 0; j < M; ++j)
+      cin >> A(i, j);
+  for (size_t i = 0; i < M; ++i)
+    for (size_t j = 0; j < K; ++j)
+      cin >> B(i, j);
+  auto C = A * B;
+  for (size_t i = 0; i < N; ++i)
+    for (size_t j = 0; j < K; ++j)
+      cout << C(i, j) << " \n"[j + 1 == K];
+  return 0;
+}