1639. 拓扑顺序

Posted 2021-05-23 幽殇默

https://www.acwing.com/problem/content/description/1641/

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<queue>
using namespace std;
const int N=1e3+10;
const int M=1e4+10;
int h[N],e[M],ne[M],idx;
int d[N],backup[N];
int n,m;
void add(int a,int b)
{
	e[idx]=b,ne[idx]=h[a],h[a]=idx++;
}
bool topsort(int a[])
{
	memcpy(backup,d,sizeof d);
	for(int i=0;i<n;i++)
	{
		int t=a[i];
		if(backup[t]!=0) return true;
		for(int j=h[t];j!=-1;j=ne[j])
		{
			int k=e[j];
			if(backup[k]!=0) backup[k]--;
		}
	}
	for(int i=1;i<=n;i++) if(backup[i]) return true;
	return false;
}
int main(void)
{
    memset(h,-1,sizeof h);
	cin>>n>>m;
	while(m--)
	{
		int a,b; cin>>a>>b;
		add(a,b);
		d[b]++;
	}
	int t; cin>>t;
	for(int i=0;i<t;i++)
	{
		int a[N];
		for(int  j=0;j<n;j++) cin>>a[j];
		if(topsort(a)) cout<<i<<" ";
	}
	return 0;
}