1191. 家谱树 拓扑排序

Posted 2021-05-23 幽殇默

https://www.acwing.com/problem/content/description/1193/

#include<cstdio>
#include<iostream>
#include<cstring>
#include<algorithm>
#include<queue>
#include<vector>
using namespace std;
const int N=110;
const int M=660;
int h[N],e[M],ne[M],idx;
int d[N];
int n;
vector<int> ans;
void add(int a,int b)
{
	e[idx]=b,ne[idx]=h[a],h[a]=idx++;
}
void topsort()
{
	queue<int> q;
	for(int i=1;i<=n;i++)
	if(!d[i]) q.push(i),ans.push_back(i);
	
	while(q.size())
	{
		int t=q.front(); q.pop();
		for(int i=h[t];i!=-1;i=ne[i])
		{
			int j=e[i];
			if(--d[j]==0)
			{
				q.push(j);
				ans.push_back(j);
			}
		}
	}
}
int main(void)
{
	memset(h,-1,sizeof h);
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		int x;
		while(cin>>x,x!=0)
		{
			add(i,x);
			d[x]++;
		}
	}
	topsort();
	for(int i=0;i<ans.size();i++) cout<<ans[i]<<" ";
	return 0;
}