結果

問題 No.1207 グラフX
ユーザー chocopuu
提出日時 2020-08-30 13:26:35
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 884 ms / 2,000 ms
コード長 4,513 bytes
コンパイル時間 2,593 ms
コンパイル使用メモリ 204,056 KB
最終ジャッジ日時 2025-01-13 21:10:33
ジャッジサーバーID
(参考情報)
judge3 / judge4
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 46
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ソースコード

diff #
プレゼンテーションモードにする

#include "bits/stdc++.h"
using namespace std;
#define int long long
#define REP(i, n) for (int i = 0; i < (int)n; ++i)
#define RREP(i, n) for (int i = (int)n - 1; i >= 0; --i)
#define FOR(i, s, n) for (int i = s; i < (int)n; ++i)
#define RFOR(i, s, n) for (int i = (int)n - 1; i >= s; --i)
#define ALL(a) a.begin(), a.end()
#define IN(a, x, b) (a <= x && x < b)
template<class T>istream&operator >>(istream&is,vector<T>&vec){for(T&x:vec)is>>x;return is;}
template<class T>inline void out(T t){cout << t << "\n";}
template<class T,class... Ts>inline void out(T t,Ts... ts){cout << t << " ";out(ts...);}
template<class T>inline bool CHMIN(T&a,T b){if(a > b){a = b;return true;}return false;}
template<class T>inline bool CHMAX(T&a,T b){if(a < b){a = b;return true;}return false;}
constexpr int INF = 1e18;
template<int MOD> struct Fp {
long long val;
constexpr Fp(long long v = 0) noexcept : val(v % MOD) {
if (val < 0) val += MOD;
}
constexpr int getmod() { return MOD; }
constexpr Fp operator - () const noexcept {
return val ? MOD - val : 0;
}
constexpr Fp operator + (const Fp& r) const noexcept { return Fp(*this) += r; }
constexpr Fp operator - (const Fp& r) const noexcept { return Fp(*this) -= r; }
constexpr Fp operator * (const Fp& r) const noexcept { return Fp(*this) *= r; }
constexpr Fp operator / (const Fp& r) const noexcept { return Fp(*this) /= r; }
constexpr Fp& operator += (const Fp& r) noexcept {
val += r.val;
if (val >= MOD) val -= MOD;
return *this;
}
constexpr Fp& operator -= (const Fp& r) noexcept {
val -= r.val;
if (val < 0) val += MOD;
return *this;
}
constexpr Fp& operator *= (const Fp& r) noexcept {
val = val * r.val % MOD;
return *this;
}
constexpr Fp& operator /= (const Fp& r) noexcept {
long long a = r.val, b = MOD, u = 1, v = 0;
while (b) {
long long t = a / b;
a -= t * b; swap(a, b);
u -= t * v; swap(u, v);
}
val = val * u % MOD;
if (val < 0) val += MOD;
return *this;
}
constexpr bool operator == (const Fp& r) const noexcept {
return this->val == r.val;
}
constexpr bool operator != (const Fp& r) const noexcept {
return this->val != r.val;
}
friend constexpr ostream& operator << (ostream &os, const Fp<MOD>& x) noexcept {
return os << x.val;
}
friend constexpr Fp<MOD> modpow(const Fp<MOD> &a, long long n) noexcept {
if (n == 0) return 1;
auto t = modpow(a, n / 2);
t = t * t;
if (n & 1) t = t * a;
return t;
}
};
template<class T> struct BiCoef {
vector<T> fact_, inv_, finv_;
constexpr BiCoef() {}
constexpr BiCoef(int n) noexcept : fact_(n, 1), inv_(n, 1), finv_(n, 1) {
init(n);
}
constexpr void init(int n) noexcept {
fact_.assign(n, 1), inv_.assign(n, 1), finv_.assign(n, 1);
int MOD = fact_[0].getmod();
for(int i = 2; i < n; i++){
fact_[i] = fact_[i-1] * i;
inv_[i] = -inv_[MOD%i] * (MOD/i);
finv_[i] = finv_[i-1] * inv_[i];
}
}
constexpr T com(int n, int k) const noexcept {
if (n < k || n < 0 || k < 0) return 0;
return fact_[n] * finv_[k] * finv_[n-k];
}
constexpr T P(int n, int k) const noexcept {
if (n < k || n < 0 || k < 0) return 0;
return fact_[n] * finv_[n-k];
}
constexpr T fact(int n) const noexcept {
if (n < 0) return 0;
return fact_[n];
}
constexpr T inv(int n) const noexcept {
if (n < 0) return 0;
return inv_[n];
}
constexpr T finv(int n) const noexcept {
if (n < 0) return 0;
return finv_[n];
}
};
const int MOD = 1000000007;
// const int MOD = 998244353;
using mint = Fp<MOD>;
BiCoef<mint> bc;
// bc.init(500050);
struct UF{
vector<int>par,sz;
void init(int n){
par.resize(n);
sz.resize(n);
for(int i=0;i<n;i++){
par[i]=i;
sz[i]=1;
}
}
int find(int x){
return x==par[x]?x:par[x]=find(par[x]);
}
void unite(int x,int y){
x=find(x);y=find(y);
if(x==y)return;
sz[x]+=sz[y];
par[y]=x;
}
bool same(int x,int y){
return find(x)==find(y);
}
int size(int x){
return sz[find(x)];
}
};
signed main(){
int N, M, X;
cin >> N >> M >> X;
UF uf;
uf.init(N);
vector<vector<pair<int,int>>>g(N);
REP(i, M) {
int x, y, z;
cin >> x >> y >> z;
--x; --y;
if(!uf.same(x, y)) {
uf.unite(x, y);
g[x].emplace_back(y, z);
g[y].emplace_back(x, z);
}
}
vector<int>sz(N, 1);
mint ans = 0;
auto dfs = [&](auto&&f, int now, int par) -> int {
//out(now);
for(auto[to, cost]: g[now]) {
if(to == par) continue;
sz[now] += f(f, to, now);
ans += modpow((mint)X, cost) * sz[to] * (N - sz[to]);
}
return sz[now];
};
dfs(dfs, 0, -1);
out(ans);
}
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