Add -pedantic, -Werror to compilation flags

Author: adamant-pwn

.verify-helper/config.toml

@@ -1,3 +1,3 @@
 [[languages.cpp.environments]]
 CXX = "g++"
-CXXFLAGS = ["-std=c++23", "-Wall", "-Wextra", "-O2", "-march=native"]
+CXXFLAGS = ["-std=c++23", "-Wall", "-Wextra", "-pedantic", "-Werror", "-O2", "-march=native"]

verify/data_structures/bitpack/system_mod_2.test.cpp

@@ -13,7 +13,7 @@ bitpack<maxn> a[maxn];
 void solve() {
     int n, m;
     cin >> n >> m;
-    string As[n];
+    vector<string> As(n);
     for(int i = 0; i < n; i++) {
         cin >> As[i];
     }

verify/poly/roots.test.cpp

@@ -15,7 +15,7 @@ void find_roots_impl(polyn const& p, vector<base> &res) {
     if(p.deg() == 1) {
         res.push_back(-p[0] / p[1]);
     } else if(p.deg() > 1) {
-        auto A = polyn::gcd(polyn(vector<base>{rng(), 1}).powmod((mod - 1) / 2, p) - base(1), polyn(p));
+        auto A = polyn::gcd(polyn(vector<base>{(base)rng(), 1}).powmod((mod - 1) / 2, p) - base(1), polyn(p));
         find_roots_impl(A, res);
         find_roots_impl(p / A, res);
     }