有向无环图中的拓扑排序

#include <bits/stdc++.h>
using namespace std;

const int maxn=100000+15;
const int maxm=100000+15;
struct Edge
{
    int x,y,next;
    Edge(int x=0,int y=0,int next=0):x(x),y(y),next(next){}
}edge[maxm];
int sumedge,head[maxn];
int n,m;
int ins(int x,int y)
{
    edge[++sumedge]=Edge(x,y,head[x]);
    return head[x]=sumedge;
}
int h,t,line[maxn],ind[maxn];
int money[maxn];
bool boo[maxn];
int main()
{
    scanf("%d%d",&n,&m);
    for (int i=1;i<=m;i++)
    {
        int u,v;
        scanf("%d%d",&u,&v);
        ins(u,v);
        ind[v]++;
    }
    h=1;t=0;
    int ss=888;
    for (int i=1;i<=n;i++)
     if (ind[i]==0)
         line[++t]=i,money[i]=ss;
//    dp[i]=max(dp[j])+1 ((j,i))
    for (;h<=t;) 
    {
        ss++;
        int now=t;
        for (;h<=now;h++)
         for (int u=head[line[h]];u;u=edge[u].next)
         {
            ind[edge[u].y]--;
            if (ind[edge[u].y]==0) 
             line[++t]=edge[u].y,money[i]=ss;
         }
    }
    for (int i=1;i<=n;i++) printf("%d ",line[i]);
    printf("\n");
    return 0;
 }