dijkstra板子

int dist[MAXN];
bool vis[MAXN];
priority_queue<pair<int ,int > >dd;
void dij(){
	memset(vis,0,sizeof(vis));
	memset(dist,0x7f,sizeof(dist));
	dist[1]=0;
	dd.push(make_pair(0,1));
	while(!dd.empty()){
		int ltop=dd.top().second;dd.pop();
//		cout<<ltop<<endl;
		if(vis[ltop])continue;
		vis[ltop]=1;
		int base=dist[ltop];
		for(int i=head[ltop];i;i=bl[i].nt){
			if(base+bl[i].w>=dist[bl[i].to])continue;
			dist[bl[i].to]=base+bl[i].w;
			dd.push(make_pair(-dist[bl[i].to],bl[i].to));
		}
	}
}