結果
問題 | No.1207 グラフX |
ユーザー |
|
提出日時 | 2020-08-30 16:20:38 |
言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 239 ms / 2,000 ms |
コード長 | 4,477 bytes |
コンパイル時間 | 1,110 ms |
コンパイル使用メモリ | 88,364 KB |
最終ジャッジ日時 | 2025-01-13 23:50:02 |
ジャッジサーバーID (参考情報) |
judge5 / judge5 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 3 |
other | AC * 46 |
ソースコード
#include <iostream>#include <numeric>#include <vector>template <int MOD>struct ModInt {using lint = long long;int val;// constructorModInt(lint v = 0) : val(v % MOD) {if (val < 0) val += MOD;};// unary operatorModInt operator+() const { return ModInt(val); }ModInt operator-() const { return ModInt(MOD - val); }ModInt inv() const { return this->pow(MOD - 2); }// arithmeticModInt operator+(const ModInt& x) const { return ModInt(*this) += x; }ModInt operator-(const ModInt& x) const { return ModInt(*this) -= x; }ModInt operator*(const ModInt& x) const { return ModInt(*this) *= x; }ModInt operator/(const ModInt& x) const { return ModInt(*this) /= x; }ModInt pow(lint n) const {auto x = ModInt(1);auto b = *this;while (n > 0) {if (n & 1) x *= b;n >>= 1;b *= b;}return x;}// compound assignmentModInt& operator+=(const ModInt& x) {if ((val += x.val) >= MOD) val -= MOD;return *this;}ModInt& operator-=(const ModInt& x) {if ((val -= x.val) < 0) val += MOD;return *this;}ModInt& operator*=(const ModInt& x) {val = lint(val) * x.val % MOD;return *this;}ModInt& operator/=(const ModInt& x) { return *this *= x.inv(); }// comparebool operator==(const ModInt& b) const { return val == b.val; }bool operator!=(const ModInt& b) const { return val != b.val; }bool operator<(const ModInt& b) const { return val < b.val; }bool operator<=(const ModInt& b) const { return val <= b.val; }bool operator>(const ModInt& b) const { return val > b.val; }bool operator>=(const ModInt& b) const { return val >= b.val; }// I/Ofriend std::istream& operator>>(std::istream& is, ModInt& x) noexcept {lint v;is >> v;x = v;return is;}friend std::ostream& operator<<(std::ostream& os, const ModInt& x) noexcept { return os << x.val; }};template <class Cost = int>struct Edge {int src, dst;Cost cost;Edge(int src = -1, int dst = -1, Cost cost = 1): src(src), dst(dst), cost(cost){};bool operator<(const Edge<Cost>& e) const { return this->cost < e.cost; }bool operator>(const Edge<Cost>& e) const { return this->cost > e.cost; }};template <class Cost = int>struct Graph {std::vector<std::vector<Edge<Cost>>> graph;Graph(int n = 0) : graph(n) {}void span(bool direct, int src, int dst, Cost cost = 1) {graph[src].emplace_back(src, dst, cost);if (!direct) graph[dst].emplace_back(dst, src, cost);}int size() const { return graph.size(); }void clear() { graph.clear(); }void resize(int n) { graph.resize(n); }std::vector<Edge<Cost>>& operator[](int v) { return graph[v]; }std::vector<Edge<Cost>> operator[](int v) const { return graph[v]; }};struct UnionFind {std::vector<int> par, sz;int gnum;explicit UnionFind(int n): par(n), sz(n, 1), gnum(n) {std::iota(par.begin(), par.end(), 0);}int find(int v) {return (par[v] == v) ? v : (par[v] = find(par[v]));}void unite(int u, int v) {u = find(u), v = find(v);if (u == v) return;if (sz[u] < sz[v]) std::swap(u, v);sz[u] += sz[v];par[v] = u;--gnum;}bool same(int u, int v) { return find(u) == find(v); }bool ispar(int v) { return v == find(v); }int size(int v) { return sz[find(v)]; }};constexpr int MOD = 1000000007;using mint = ModInt<MOD>;void solve() {int n, m;mint x;std::cin >> n >> m >> x;Graph<int> graph(n);UnionFind uf(n);while (m--) {int u, v, w;std::cin >> u >> v >> w;if (uf.same(--u, --v)) continue;uf.unite(u, v);graph.span(false, u, v, w);}mint ans = 0;auto dfs = [&](auto f, int v, int p) -> int {int sz = 1;for (auto e : graph[v]) {int u = e.dst;if (u == p) continue;int csz = f(f, u, v);ans += x.pow(e.cost) * csz * (n - csz);sz += csz;}return sz;};dfs(dfs, 0, -1);std::cout << ans << "\n";}int main() {std::cin.tie(nullptr);std::ios::sync_with_stdio(false);solve();return 0;}