noip提高组图论模板

//拓扑排序
void Top(){
	for(i=1;i<=n;++i)
		if(!du[i]) q.push(i);
	while(!q.empty()){
		int u=q.front();q.pop();
		ans[++num]=u;
		for(int i=head[u];i;i=nxt[i]){
			int t=to[i];
			if(!--du[t]) q.push(t);
		}
	}
}
//有向图tarjan
void tarjan(int cur){
	dfn[cur]=low[cur]=++sign;
	sta[++top]=cur,insta[cur]=1;
	for(int i=first[cur];i;i=next[i]){
		int t=to[i];
		if(!dfn[t]) tarjan(t),low[cur]=min(low[cur],low[t]);
		else if(insta[t]&&low[cur]>dfn[t]) low[cur]=dfn[t];
	}
	if(low[cur]==dfn[cur]){
		do{insta[sta[top]]=0,id[sta[top]=++sum;}while(sta[top--]!=cur);
	}
}
//无向图tarjan
void tarjan(int cur,int in_E){
	dfn[cur]=low[cur]=++sign;
	for(int i=first[cur];i;i=next[i]){
		int t=to[i];
		if(!dfn[t]){
			tarjan(t,i);
			low[cur]=min(low[cur],low[t]);
			if(low[t]>dfn[cur]){ 
				bridge[i]=bridge[i^1]=1;
			}
		}
		else if(i!=(in_E^1)){
			low[cur]=min(low[cur],dfn[t]);
		}
	}
}
void Make_id(int cur,int Id){
	id[cur]=Id;
	for(int i=first[cur];i;i=next[i]){
		int t=to[i];
		if(id[t]||bridge[i]) continue;
		Make_id(t,Id);
	}
}  
//dijkstra
int dfs(int st,int ed){
	memset(dis,127,sizeof(dis));
	q.push(make_pair(0,st)); dis[st]=0;
	while(!q.empty()){
		int u=q.top().second; q.pop();
		for(int i=first[u];i;i=next[i]){
			int t=to[i];
			if(dis[t]>dis[u]+w[i]){
				dis[t]=dis[u]+w[i];
				q.push(make_pair(-dis[t],t));
			}
		}
	}
	return dis[ed];
} 
//spfa
void spfa(int st){
	queue<int> q; dis[st]=0; q.push(st);
	while(!q.empty()){
	  	int x=q.front(); q.pop();
	    vis[x]=0;
		for(int i=first[x];i;i=next[i]){
			int t=to[i];
		  	if(dis[t]>dis[x]+w[i]){
		  	dis[t]=dis[x]+w[i];
		  	if(!vis[t]){vis[t]=1;q.push(t);}
		   	}
	    }
    }
}
//dfs_spfa找负环 
void dfs(int u){
    if(vis[u]){flag=1;return;}
    vis[u]=1;
    if(flag) return;
    for(int i=first[u];i;i=next[i]){
        int t=to[i];
        if(dis[t]>dis[u]+w[i]){
            dis[t]=dis[u]+w[i];
            dfs(t);
        }
    }vis[u]=0;
}
//Kruscal
void Kruskal(){
    sort(E+1,E+m+1,cmp);
    for(int i=1;i<=n;i++)father[i]=i;
    for(int i=1;i<=m;i++){
        int x=find(E[i].u),y=find(E[i].v);
        if(x!=y){
            father[x]=y;
            add(x,y,E[i].w),add(y,x,E[i].w);
        }
    }
}