拓扑排序模板

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<queue>
using namespace std;
int indegree[100];
queue<int> q;
int n,m;
bool map[100][100];
int a[100];
int topo(int n)
{
    int cnt = 1;
    while(!q.empty())
        q.pop();
    for(int i = 1; i <= n ; i++)
        if(indegree[i] == 0)
            q.push(i);
    int u;
    while(!q.empty()){
        u = q.front();
        a[cnt++] = u;
        q.pop();
        for(int i = 1; i <= n ; i++){
            if(map[u][i]){
                indegree[i] --;
                if(indegree[i] == 0)
                    q.push(i);
            }
        }
        if(cnt == n){
            for(int i = 1 ; i <= n ; i++)
                printf(" %d",a[i]);
        }
        else printf("The network has a cycle");
    }
}
int main()
{
    int u,v;
    while(~scanf("%d%d",&n,&m)){
        memset(indegree,0,sizeof(indegree));
        memset(map,0,sizeof(map));
        for(int i = 0 ; i < m ; i++){
            scanf("%d%d",&u,&v);
            if(!map[u][v])
                indegree[v]++;
                map[u][v] = 1;
        }
               topo(n);
    }
    return 0;
}

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<queue>
using namespace std;
const int M = 100005;
struct Edge
{
    int v,nxt;
    Edge() {}
    Edge(int v,int nxt): v(v),nxt(nxt){}
}e[M];
int head[M],E;
int a[M];
int indegree[M];
int n,m,u,v;
void addedge()
{
    e[E] = Edge(v, head[u]);
    head[u] = E++;
}
void inti()
{
    E = 0;
    memset(head,-1,sizeof(head));
    memset(a,0,sizeof(a));
    memset(indegree,0,sizeof(indegree));
}
void topo(int n)
{
    queue<int> q;
    int cnt = 1;
    while(!q.empty()) q.pop();
    for(int i = 1; i <= n ; i++)
        if(indegree[i] == 0 )
            q.push(i);
    while(!q.empty()){
        int u = q.front();
        a[cnt++] = u;
        q.pop();
        for(int i = head[u]; ~u; i = e[i].nxt){
            indegree[e[i].v]--;
            if(indegree[e[i].v] == 0 ) 
                q.push(e[i].v);
        }
    }
}
int main()
{
    while(~scanf("%d%d",&n,&m)){
        for(int i = 1; i <= m ; i++){
            scanf("%d%d",&u,&v);
                indegree[v]++;
                addedge();
        }
        topo(n);
    }
    return 0;
}