<span style="font-size:12px;">#include<cstdio>
#include<cstring>
int ans[510][510];//记录两人是否进行了比赛 
int n,indegree[510];//记录前驱个数 
int queue[510];//保存拓扑 

void tuopu()
{
	int i,j,top,k=0;
	for(j=0;j<n;++j)
	{
		for(i=1;i<=n;++i)
		{
			if(indegree[i]==0)//前驱为零即是当前第一名 
			{
				top=i;
				break;
			}
		}
		queue[k++]=top;//当前第一名入队列 
		indegree[top]=-1;//前驱数量更新为-1，避免重复入队列 
		for(i=1;i<=n;++i)
		{
			if(ans[top][i])//将前驱中含有当前第一名的前去数量减一 
			   indegree[i]--;
		}
	}
	for(i=0;i<k-1;++i)
	   printf("%d ",queue[i]);
	printf("%d\n",queue[n-1]);
} 

int main()
{
	int i,a,b,m;
	while(scanf("%d%d",&n,&m)!=EOF)
	{
		memset(indegree,0,sizeof(indegree));
		memset(ans,0,sizeof(ans));
		for(i=0;i<m;++i)
		{
			scanf("%d%d",&a,&b);
			if(ans[a][b]==0)
			{
				ans[a][b]=1;//记录是否进行了比赛 
			    indegree[b]++;//记录前驱数量 
			}
		}
		tuopu();
	} 
	return 0;
}</span>

<span style="font-size:12px;">#include<cstdio>
#include<cstring>
int n,indegree[510];
int queue[510],head[510];

struct node
{
	int to,next;
}ans[510];

void tuopu()
{
	int i,j,top,k=0,cnt;
	for(j=0;j<n;++j)
	{
		for(i=1;i<=n;++i)
		{
			if(indegree[i]==0)
			{
				top=i;
				break;
			}
		}
		queue[k++]=top;
		indegree[top]=-1;
		for(cnt=head[top];cnt!=-1;cnt=ans[cnt].next)//邻接表，看不懂，可以找数据模拟几遍 
		    indegree[ans[cnt].to]--;
	}
	for(i=0;i<n-1;++i)
	   printf("%d ",queue[i]);
	printf("%d\n",queue[n-1]);
} 

int main()
{
	int i,a,b,m;
	while(scanf("%d%d",&n,&m)!=EOF)
	{
		memset(indegree,0,sizeof(indegree));
		memset(head,-1,sizeof(head));
		for(i=0;i<m;++i)
		{
			scanf("%d%d",&a,&b);
			ans[i].to=b;//建表 
			ans[i].next=head[a];
			head[a]=i;	
			indegree[b]++;		
		}
		tuopu();
	}
	return 0;
}</span>

<span style="font-size:12px;">#include<cstdio>
#include<cstring>
#include<queue>
using namespace std;
int ans[510][510];
int n,indegree[510];

void tuopu()
{
	int i,j,t,top;
	queue<int>q;
    for(i=1;i<=n;++i)
    {
    	if(indegree[i]==0)
    	{
    		q.push(i);
    		break;
    	}    
    }
    int sign=1;
    while(!q.empty())
    {
    	top=q.front();
    	q.pop();
    	indegree[top]=-1;
    	if(sign)
    	{
    		printf("%d",top);
    		sign=0;
    	}
    	else   
		    printf(" %d",top);
		for(i=1;i<=n;++i)//注意，以当前第一名为前驱的点的前驱数量都要减少 
	    {
	    	if(ans[top][i]==1)
	    	   indegree[i]--;
	    }
		for(i=1;i<=n;++i)
		{
			if(indegree[i]==0)
			{
				q.push(i);
				break;
			}
		}
    }
    printf("\n");
} 

int main()
{
	int i,m,a,b;
	while(scanf("%d%d",&n,&m)!=EOF)
	{
		memset(indegree,0,sizeof(indegree));
		memset(ans,0,sizeof(ans));
		for(i=0;i<m;++i)
		{
			scanf("%d%d",&a,&b);
			if(ans[a][b]==0)
			{
				ans[a][b]=1;
				indegree[b]++;
			}
		}
		tuopu();
	}
	return 0;
}</span>

<span style="font-size:12px;">#include<cstdio>
#include<cstring>
#include<queue>
using namespace std;
int ans[510][510];
int n,indegree[510];

void tuopu()
{
	int i,j,t,top;
	priority_queue<int,vector<int>,greater<int> >q;//从小到大排序 
    for(i=1;i<=n;++i)
    {
    	if(indegree[i]==0)
    		q.push(i);
    }
    int sign=1;
    while(!q.empty())
    {
    	top=q.top();
    	q.pop();
    	indegree[top]=-1;
    	if(sign)
    	{
    		printf("%d",top);
    		sign=0;
    	}
    	else   
		    printf(" %d",top);
		for(i=1;i<=n;++i)
		{
			if(ans[top][i])
			{
				indegree[i]--; 
			    if(indegree[i]==0)
				    q.push(i);
			} 
			  
		}
    }
    printf("\n");
} 

int main()
{
	int i,m,a,b;
	while(scanf("%d%d",&n,&m)!=EOF)
	{
		memset(indegree,0,sizeof(indegree));
		memset(ans,0,sizeof(ans));
		for(i=0;i<m;++i)
		{
			scanf("%d%d",&a,&b);
			if(ans[a][b]==0)
			{
				ans[a][b]=1;
				indegree[b]++;
			}
		}
		tuopu();
	}
	return 0;
}</span>