dijkstra

struct cmp { //优先队列的比较函数
	bool operator()(int a, int b) {
		return dist[a] > dist[b]; 
	}
};
void dijkstra(int start) {
	priority_queue<int, vector<int>, cmp> q; 

	q.push(start);
	dist[start] = 0;

	while (!q.empty()) {
		int u = q.top();
		q.pop();

		if (visit[u]) continue;

		visit[u] = true;
		for (int i = head[u]; i; i = Next[i]) { //邻接表，遍历以 u 为起点的所有路径
			int v = destination[i];      // v是当前路径的终点
			if (!visit[v] && dist[v] > dist[u] + (long long)edgeLen[i]) {
				dist[v] = dist[u] + edgeLen[i];
				q.push(v);
			}
		}

	}
}