[알고리즘] 백준 12384번: 주간 미팅 (C++)

https://www.acmicpc.net/problem/12834

12834번: 주간 미팅

간단한 다익스트라 문제다.

갈 수 없는 길이 나올 땐 -1 처리를 해주고, 모든 최단 경로를 더한 값을 출력하면 된다.

#include <iostream>
#include <queue>
#include <vector>
#include <utility>
#define MAX 1000 + 1
#define INF 987654321
#define pii pair<int, int>
using namespace std;

vector<pii> graph[MAX];
int n, v, e;

struct cmp {
	bool operator()(pii& a, pii& b) {
		return a.second > b.second;
	}
};

vector<int> dijkstra(int node) {
	vector<int> dist(v + 1, INF);
	dist[node] = 0;
	priority_queue<pii, vector<pii>, cmp> pq;
	pq.push({ node, 0 });
	while (!pq.empty()) {
		int now = pq.top().first;
		int cost = pq.top().second;

		pq.pop();
		if (dist[now] < cost) {
			continue;
		}

		for (int i = 0; i < graph[now].size(); i++) {
			int next = graph[now][i].first;
			int nextCost = graph[now][i].second;
			if (cost + nextCost < dist[next]) {
				dist[next] = cost + nextCost;
				pq.push({ next, dist[next] });
			}
		}
	}

	return dist;
}
int main() {
	cin >> n >> v >> e;
	int a, b;
	cin >> a >> b;

	vector<int> team;
	for (int i = 1, value; i <= n; i++) {
		cin >> value;
		team.push_back(value);
	}

	for (int i = 0; i < e; i++) {
		int start, end, w;
		cin >> start >> end >> w;
		graph[start].push_back({ end, w });
		graph[end].push_back({ start, w });
	}

	int sum = 0;
	for (int i = 0; i < team.size(); i++) {
		vector<int> temp = dijkstra(team[i]);
		if (temp[a] == INF) sum += -1;
		else sum += temp[a];

		if (temp[b] == INF) sum += -1;
		else sum += temp[b];
	}
	cout << sum;
	return 0;
}