Toop排序

#include <iostream>
using namespace std;

const int N = 100010;
int n,m;
int Value[N];//存储节点 
int Next[N];//记录下一个节点的下标 
int Head[N];//记录头结点 
int Index;//存储位置 
int Degree[N];//记录每个节点的入度 
int Queue[N];//手工模拟的队列 


void Add(int Start, int End)
{
	Value[Index] = End;
	Next[Index] = Head[Start];
	Head[Start] = Index;
	Index++; 
}

bool ToopSort()
{
	//队列的头尾 
	int Start = 0;
	int End = -1;
	
	for(int i = 1; i <= n; i++)
	{
		if(!Degree[i])
		{
			Queue[++End] = i;
		}
	}
	
	while(Start <= End)
	{
		int NodeHead = Queue[Start++];
		
		for(int i = Head[NodeHead]; i != -1; i = Next[i])
		{
			int j = Value[i];
			Degree[j]--;
			if(0 == Degree[j])
			{
				Queue[++End] = j;
			}
		}
	}
	
	return End == (n-1);
}
 
int main(int argc, char** argv) 
{
	//初始化头结点都为-1 代表没有后继元素 
	fill(Head,Head+N,-1);
	
	cin>>n>>m;
	
	for(int i = 0; i < m; i++)
	{
		int Start,End;
		scanf("%d%d",&Start,&End);
		Add(Start,End);
		//入度+1 
		Degree[End]++;
	}
	
	if(ToopSort())
	{
		for(int i = 0; i < n; i++)
		{
			printf("%d ",Queue[i]);	
		}	
	}
	else
	{
		cout<<"-1"<<endl; 
	}
	return 0;
}