模板之拓扑排序&优先队列

#include<vector>
#include<cstdio>
#include<queue>
#define maxv 1010
using namespace std;
vector<int> G[maxv];
vector<int> res;
int n,m,inDegree[maxv],num=0;
bool (){
	num=0;
	priority_queue<int, vector<int>,greater<int>> q;
	for(int i=0;i<n;i++){
		if(inDegree[i]==0){
			q.push(i);
		}
	}
	while(!q.empty()){
		int u = q.top();
		res.push_back(u);
		q.pop();
		for(int i=0;i<G[u].size();i++){
			int v=G[u][i];
			inDegree[v]--;
			if(inDegree[v]==0){
				q.push(v);
			}
		}
	
		num++;
	}
	if(num==n) return true;
	else return false;
}
int main(){
	for(int i=0;i<maxv;i++){
		inDegree[i]=0;
	}
	cin>>n>>m;
	for(int i=0;i<m;i++){
		int a,b;
		scanf("%d%d",&a,&b);
		G[a].push_back(b);
		inDegree[b]++;
	}
	if(ts()){
		cout<<"YES"<<endl;
		int i;
		for(i=0;i<res.size()-1;i++){
			cout<<res[i]<<" ";
		}
		cout<<res[i];
	}else{
	cout<<"NO"<<endl;
	cout<<n-num;
	} 
	
}