自定义队列的例子

#include <iostream>
#include <bits/stdc++.h>
using namespace std;
vector<int> adj[101];
int in[101];
void topsort(int n)
{
    
    
    int *que;
    int next;
    que = new int[n + 1];
    int font, real;
    int m;
    font = real = 0;
    for (int k = 1; k <= n; k++)
    {
    
    
        if (in[k] == 0)
        {
    
    
             cout<<"in["<<k<<"] is 0"<<endl;
            que[real++] = k;
             cout<<real<<"  is  real"<<endl;
            // 进去
        }
    }
    while (font != real)
    {
    
    
       m=que[font++];
       for( int j=0;j<adj[m].size();j++){
    
    
       next=adj[m][j];
       in[next]--;
       cout<< " m is :"<<m<<" __ next is:"<<next<<endl;
       if(in[next]==0){
    
    
         que[real++]=next;
         cout<<real<<"  is in que"<<endl;
         }
       }
    }
    if(real!=n){
    
    
        cout<<"0";
        }
    else 
  cout<<"1";
    return ;

}
int main()
{
    
    
    int n;
    int node1, node2;
    int num;
    cin >> n;
    cout<<" n is "<<n<<endl;
    for (int i = 1; i <= n; i++)
    {
    
    
        cin >> num;
        if (num!=0)
        {
    
    
            for (int j = 1; j <=num; j++)
            {
    
    
                cin >> node1;
                in[i]++;
                adj[node1].push_back(i);
                cout<<i<<" is in adj["<<node1<<"]"<<endl;
            }
        }
    }
    topsort(n);
}

本身代码是没有什么好说的，只是在计算in[next]–;时候错误写成了in[next–];
导致出现了段错误， 看来调试是个好东西。