Submission #24947786

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Source Code Expand

#include "bits/stdc++.h"

#define int long long

using namespace std;
using ll = long long;
using P = pair<ll, ll>;
const ll INF = (1LL << 61);
ll mod = 1000000007;

struct UnionFind {
	vector<int>par, vsize, esize;
	UnionFind();
	UnionFind(int sz_) : par(sz_), vsize(sz_, 1), esize(sz_, 0) {
		for (int i = 0; i < sz_; i++)par[i] = i;
	}
	void init(int sz_) {
		par.resize(sz_);
		vsize.resize(sz_, 1);
		esize.resize(sz_, 0);
		for (int i = 0; i < sz_; i++)par[i] = i;
	}
	int root(int x) {
		if (par[x] == x)return x;
		else return par[x] = root(par[x]);
	}
	bool merge(int x, int y) {
		x = root(x), y = root(y);
		if (x == y) {
			esize[x]++;
			return false;
		}
		if (vsize[x] < vsize[y])swap(x, y);
		vsize[x] += vsize[y];
		esize[x] += esize[y] + 1;
		par[y] = x;
		return true;
	}
	bool issame(int x, int y) {
		return root(x) == root(y);
	}
	int vs(int x) {
		return vsize[root(x)];
	}
	int es(int x) {
		return esize[root(x)];
	}
};
// 辺の定義
struct Edge {
	int u, v;
	int cost;
};
// 比較関数
bool comp_e(const Edge &e1, const Edge &e2) {
	return e1.cost < e2.cost;
}

signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	int N, M; cin >> N >> M;
	N++;
	vector<Edge>G(M);
	for (int i = 0; i < M; i++) {
		int C, L, R; cin >> C >> L >> R; L--;
		G[i].u = L; G[i].v = R; G[i].cost = C;
		
	}
	sort(G.begin(), G.end(), comp_e);
	UnionFind uf(N);
	int sum = 0;
	for (auto e : G) {
		if (!uf.issame(e.u, e.v)) { // 閉路になければ加える
			uf.merge(e.u, e.v);
			sum += e.cost;
		}
	}
	set<int>st;
	for (int i = 0; i < N; i++)st.insert(uf.root(i));
	if ((int)st.size() > 1)cout << -1 << endl;
	else cout << sum << endl;
	return 0;


}

Submission Info

Judge Result