結果

問題 No.1207 グラフX
ユーザー suta28407928suta28407928
提出日時 2020-08-30 13:32:00
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 244 ms / 2,000 ms
コード長 4,321 bytes
コンパイル時間 1,405 ms
コンパイル使用メモリ 122,288 KB
実行使用メモリ 46,696 KB
最終ジャッジ日時 2024-11-15 06:46:54
合計ジャッジ時間 10,082 ms
ジャッジサーバーID
（参考情報） 		judge2 / 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
権限があれば一括ダウンロードができます

ソースコード

diff # 

#include <iostream>
#include <string>
#include <cstdlib>
#include <cmath>
#include <vector>
#include <unordered_map>
#include <map>
#include <set>
#include <algorithm>
#include <queue>
#include <stack>
#include <functional>
#include <bitset>
#include <assert.h>
#include <unordered_map>
#include <fstream>
#include <ctime>
#include <complex>
using namespace std;
typedef long long ll;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<char> vc;
typedef vector<string> vs;
typedef vector<bool> vb;
typedef vector<double> vd;
typedef pair<ll,ll> P;
typedef pair<int,int> pii;
typedef vector<P> vpl;
typedef tuple<ll,ll,ll> tapu;
#define rep(i,n) for(int i=0; i<(n); i++)
#define REP(i,a,b) for(int i=(a); i<(b); i++)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
const int inf = 1<<30;
const ll linf = 1LL<<62;
const int MAX = 1020000;
ll dy[8] = {1,-1,0,0,1,-1,1,-1};
ll dx[8] = {0,0,1,-1,1,-1,-1,1};
const double pi = acos(-1);
const double eps = 1e-7;
template<typename T1,typename T2> inline bool chmin(T1 &a,T2 b){
	if(a>b){
		a = b; return true;
	}
	else return false;
}
template<typename T1,typename T2> inline bool chmax(T1 &a,T2 b){
	if(a<b){
		a = b; return true;
	}
	else return false;
}
template<typename T> inline void print(T &a){
    rep(i,a.size()) cout << a[i] << " ";
    cout << "\n";
}
template<typename T1,typename T2> inline void print2(T1 a, T2 b){cout << a << " " << b << "\n";}
template<typename T1,typename T2,typename T3> inline void print3(T1 a, T2 b, T3 c){
	cout << a << " " << b << " " << c << "\n";
}
ll pcount(ll x) {return __builtin_popcountll(x);}
const int mod = 1e9 + 7;
//const int mod = 998244353;

template <std::uint_fast64_t Modulus> class modint {
  using u64 = std::uint_fast64_t;

public:
  u64 a;

  constexpr modint(const u64 x = 0) noexcept : a(x % Modulus) {}
  constexpr u64 &value() noexcept { return a; }
  constexpr const u64 &value() const noexcept { return a; }
  constexpr modint operator+(const modint rhs) const noexcept {
	return modint(*this) += rhs;
  }
  constexpr modint operator-(const modint rhs) const noexcept {
	return modint(*this) -= rhs;
  }
  constexpr modint operator*(const modint rhs) const noexcept {
	return modint(*this) *= rhs;
  }
  constexpr modint operator/(const modint rhs) const noexcept {
	return modint(*this) /= rhs;
  }
  constexpr modint &operator+=(const modint rhs) noexcept {
	a += rhs.a;
	if (a >= Modulus) {
	  a -= Modulus;
	}
	return *this;
  }
  constexpr modint &operator-=(const modint rhs) noexcept {
	if (a < rhs.a) {
	  a += Modulus;
	}
	a -= rhs.a;
	return *this;
  }
  constexpr modint &operator*=(const modint rhs) noexcept {
	a = a * rhs.a % Modulus;
	return *this;
  }
  constexpr modint &operator/=(modint rhs) noexcept {
	u64 exp = Modulus - 2;
	while (exp) {
	  if (exp % 2) {
		*this *= rhs;
	  }
	  rhs *= rhs;
	  exp /= 2;
	}
	return *this;
  }
};

using mint = modint<mod>;

ll modpow(ll x, ll n, ll mod){
	ll res = 1;
	while(n > 0){
		if(n & 1) res = res * x % mod;
		x = x * x % mod;
		n >>= 1;
	}
	return res;
}

struct UnionFind{
	vl p;
	vl rank;
	vl cnt;

	UnionFind(ll n){
		rank.resize(n,0);
		p.resize(n,0);
		cnt.resize(n,0);
		rep(i,n){
			p[i] = i;
			rank[i] = 0;
			cnt[i] = 1;
		}
	}

	ll find(ll x){
		if(x != p[x]) p[x] = find(p[x]);
		return p[x];
	}

	bool same(ll x, ll y){
		return find(x) == find(y);
	}

	void unite(ll x, ll y){
		x = find(x);
		y = find(y);
		if(x == y) return;
		if(rank[x] > rank[y]){
			p[y] = x;
			cnt[x] += cnt[y];
		}else{
			p[x] = y;
			cnt[y] += cnt[x];
			if(rank[x] == rank[y]) rank[y]++;
		}
	}

	ll size(ll x){
		return cnt[find(x)];
	}
};

int main(){
	ll n,m,x; cin >> n >> m >> x;
	vector<tapu> edge(m);
	rep(i,m){
		ll x,y,z; scanf("%lld%lld%lld",&x,&y,&z); x--; y--;
		edge[i] = tie(z,x,y);
	}
	sort(all(edge));
	UnionFind uf(n);
	vector<vpl> G(n);
	rep(i,m){
		ll x,y,z;
		tie(z,x,y) = edge[i];
		if(uf.same(x,y)) continue;
		uf.unite(x,y);
		G[x].emplace_back(y,z);
		G[y].emplace_back(x,z);
	}
	mint ans = 0;
	function<ll(ll,ll)> dfs = [&](ll u, ll p) -> ll {
		ll res = 1;
		for(auto v : G[u]){
			if(v.first == p) continue;
			ll df = dfs(v.first,u);
			res += df;
			mint tmp = df * (n - df);
			ans += tmp * modpow(x,v.second,mod);
		}
		return res;
	};
	dfs(0,-1);
	cout << ans.value() << "\n";
}
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