Submission #2901951

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Source Code Expand

#include <bits/stdc++.h>
#define pb push_back
#define eb emplace_back
#define allv(V) ((V).begin()),((V).end())
#define sorv(V) sort(allv(V))
#define univ(V) (V).erase(unique(allv(V)),(V).end())
#define revv(V) reverse(allv(V))
#define sz(V) ((int)(V).size())
#define upmin(a,b) (a)=min((a),(b))
#define upmax(a,b) (a)=max((a),(b))
#define rb(x) ((x)&(-(x)))
#define INF (0x3f3f3f3f)
#define INFLL (0x3f3f3f3f3f3f3f3fll)
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;

const int MAXN = 100005;
const int MAXM = 100005;
const int MAXK = 100005;

int A[MAXN];
int B[MAXM], C[MAXM], D[MAXM], O[MAXM];

int ud[MAXK*2];

ll Ans; int AnsC;
int N, M, K;

int uf(int i) { return i == ud[i] ? i : (ud[i] = uf(ud[i])); }
void uf(int a, int b) { ud[uf(b)] = uf(a); }

int main() {
	ios::sync_with_stdio(false);

	cin >> N >> M >> K;
	for(int i = 1; i <= N; i++) cin >> A[i];
	for(int i = 1; i <= M; i++) cin >> B[i] >> C[i] >> D[i];

	iota(O, O+M+1, 0);
	sort(O+1, O+M+1, [&](int a, int b) { return D[a] < D[b]; });

	iota(ud, ud+MAXK*2, 0);

	for(int oi = 1, i, a, b, c; oi <= M; oi++) {
		i = O[oi];
		a = A[B[i]]; b = A[C[i]]; c = D[i];
		if(!a) a = MAXK + B[i];
		if(!b) b = MAXK + C[i];

		if(uf(a) == uf(b)) continue;
		AnsC++; uf(a, b);
		Ans += c;
		if(AnsC == K-1) break;
	}

	printf("%lld\n", AnsC == K-1 ? Ans : -1);
	return 0;
}

Submission Info

Judge Result