sotanishy's code snippets for competitive programming
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#define PROBLEM "https://judge.yosupo.jp/problem/enumerate_triangles" #include "../../math/modint.hpp" #include "../../graph/enumerate_triangles.hpp" #include <bits/stdc++.h> using namespace std; using ll = long long; #define rep(i, s, t) for (int i = (int)(s); i < (int)(t); ++i) #define revrep(i, t, s) for (int i = (int)(t)-1; i >= (int)(s); --i) #define all(x) begin(x), end(x) template <typename T> bool chmax(T& a, const T& b) { return a < b ? (a = b, 1) : 0; } template <typename T> bool chmin(T& a, const T& b) { return a > b ? (a = b, 1) : 0; } using mint = Modint<998244353>; int main() { ios_base::sync_with_stdio(false); cin.tie(nullptr); int N, M; cin >> N >> M; vector<mint> x(N); for (auto& v : x) cin >> v; vector<vector<int>> G(N); rep(i,0,M) { int u, v; cin >> u >> v; G[u].push_back(v); G[v].push_back(u); } mint ans = 0; for (auto [a, b, c] : enumerate_triangles(G)) { ans += x[a]*x[b]*x[c]; } cout << ans << endl; }
#line 1 "test/yosupo/enumerate_triangles.test.cpp" #define PROBLEM "https://judge.yosupo.jp/problem/enumerate_triangles" #line 2 "math/modint.hpp" #include <algorithm> #include <iostream> /** * @brief Mod int */ template <int m> class Modint { using mint = Modint; static_assert(m > 0, "Modulus must be positive"); public: static constexpr int mod() { return m; } constexpr Modint(long long y = 0) : x(y >= 0 ? y % m : (y % m + m) % m) {} constexpr int val() const { return x; } constexpr mint& operator+=(const mint& r) { if ((x += r.x) >= m) x -= m; return *this; } constexpr mint& operator-=(const mint& r) { if ((x += m - r.x) >= m) x -= m; return *this; } constexpr mint& operator*=(const mint& r) { x = static_cast<int>(1LL * x * r.x % m); return *this; } constexpr mint& operator/=(const mint& r) { return *this *= r.inv(); } constexpr bool operator==(const mint& r) const { return x == r.x; } constexpr mint operator+() const { return *this; } constexpr mint operator-() const { return mint(-x); } constexpr friend mint operator+(const mint& l, const mint& r) { return mint(l) += r; } constexpr friend mint operator-(const mint& l, const mint& r) { return mint(l) -= r; } constexpr friend mint operator*(const mint& l, const mint& r) { return mint(l) *= r; } constexpr friend mint operator/(const mint& l, const mint& r) { return mint(l) /= r; } constexpr mint inv() const { int a = x, b = m, u = 1, v = 0; while (b > 0) { int t = a / b; std::swap(a -= t * b, b); std::swap(u -= t * v, v); } return mint(u); } constexpr mint pow(long long n) const { mint ret(1), mul(x); while (n > 0) { if (n & 1) ret *= mul; mul *= mul; n >>= 1; } return ret; } friend std::ostream& operator<<(std::ostream& os, const mint& r) { return os << r.x; } friend std::istream& operator>>(std::istream& is, mint& r) { long long t; is >> t; r = mint(t); return is; } private: int x; }; #line 3 "graph/enumerate_triangles.hpp" #include <vector> std::vector<std::tuple<int, int, int>> enumerate_triangles( const std::vector<std::vector<int>>& G) { const int n = G.size(); std::vector<int> deg(n); std::ranges::transform(G, deg.begin(), [&](auto& g) { return g.size(); }); std::vector<std::vector<int>> G2(n); std::vector<std::pair<int, int>> edges; for (int i = 0; i < n; ++i) { for (int j : G[i]) { if (std::make_pair(deg[i], i) < std::make_pair(deg[j], j)) { G2[i].push_back(j); edges.push_back({i, j}); } } } std::vector<std::tuple<int, int, int>> ret; std::vector<bool> used(n); for (auto& [a, b] : edges) { for (int c : G2[a]) used[c] = true; for (int c : G2[b]) { if (used[c]) { ret.push_back({a, b, c}); } } for (int c : G2[a]) used[c] = false; } return ret; } #line 5 "test/yosupo/enumerate_triangles.test.cpp" #include <bits/stdc++.h> using namespace std; using ll = long long; #define rep(i, s, t) for (int i = (int)(s); i < (int)(t); ++i) #define revrep(i, t, s) for (int i = (int)(t)-1; i >= (int)(s); --i) #define all(x) begin(x), end(x) template <typename T> bool chmax(T& a, const T& b) { return a < b ? (a = b, 1) : 0; } template <typename T> bool chmin(T& a, const T& b) { return a > b ? (a = b, 1) : 0; } using mint = Modint<998244353>; int main() { ios_base::sync_with_stdio(false); cin.tie(nullptr); int N, M; cin >> N >> M; vector<mint> x(N); for (auto& v : x) cin >> v; vector<vector<int>> G(N); rep(i,0,M) { int u, v; cin >> u >> v; G[u].push_back(v); G[v].push_back(u); } mint ans = 0; for (auto [a, b, c] : enumerate_triangles(G)) { ans += x[a]*x[b]*x[c]; } cout << ans << endl; }