convolution on multiplicative monoid test

Author: adamant-pwn

verify/poly/convolution_mul.test.cpp

@@ -0,0 +1,53 @@
+// @brief Convolution on the Multiplicative Monoid of $\mathbb Z/p\mathbb{Z}$
+#define PROBLEM "https://judge.yosupo.jp/problem/mul_modp_convolution"
+#pragma GCC optimize("Ofast,unroll-loops")
+#define CP_ALGO_CHECKPOINT
+#include <bits/stdc++.h>
+#include "blazingio/blazingio.min.hpp"
+#include "cp-algo/number_theory/euler.hpp"
+#include "cp-algo/math/fft.hpp"
+
+using namespace std;
+
+using base = cp_algo::math::modint<998244353>;
+
+void solve() {
+    int p;
+    cin >> p;
+    auto g = cp_algo::math::primitive_root(p);
+    vector<int> lg(p);
+    int64_t cur = 1;
+    for(int i = 0; i < p - 1; i++) {
+        lg[cur] = i;
+        cur *= g;
+        cur %= p;
+    }
+    base a0, b0, as = 0, bs = 0;
+    vector<base> a(p-1), b(p-1);
+    cin >> a0;
+    for(int i = 1; i <= p - 1; i++) {
+        cin >> a[lg[i]];
+        as += a[lg[i]];
+    }
+    cin >> b0;
+    for(int i = 1; i <= p - 1; i++) {
+        cin >> b[lg[i]];
+        bs += b[lg[i]];
+    }
+    base c0 = (a0 + as) * (b0 + bs) - as * bs;
+    cout << c0 << " ";
+    cp_algo::math::fft::mul(a, b);
+    for(size_t i = p-1; i < size(a); i++) {
+        a[i - (p-1)] += a[i];
+    }
+    for(int i = 1; i <= p - 1; i++) {
+        cout << a[lg[i]] << " ";
+    }
+}
+
+signed main() {
+    //freopen("input.txt", "r", stdin);
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+    solve();
+}