拓扑序不用设置深度排序，我得复习一下

#include<bits/stdc++.h>

using namespace std;
using ll =long long;
const int N =1e6+4;
int n;
int degree[N];
int head[N],e[N],net[N],cnt;
unordered_map<string,int> mmap;
unordered_map<int,string> anti_mmap;
void add(int a,int b)
{
    e[cnt]=b,net[cnt]=head[a],head[a]=cnt++;
}
int main()
{
    memset(head,-1,sizeof head);
    scanf("%d",&n);
    int node_index=1;
    getchar();
    vector<string> pre;
    for(int i=1;i<=n;i++)
    {
        //按照句号分割
        string s;
        getline(cin,s);
        istringstream ss(s);
        vector<string> cur;
        while(getline(ss,s,'.'))
        {
            if(mmap.count(s))
            {
                cur.push_back(s);
            }else{
                mmap[s]=node_index;
                anti_mmap[node_index++]=s;
                cur.push_back(s);
            }
        }
        if(pre.size()==0){
            pre=cur;
            continue;
        }

        //如果个数相等那就可以比较了
        if(cur.size()==pre.size()){
            for(int i=0;i<cur.size();i++)
            {
                if(cur[i]!=pre[i])
                {
                    add(mmap[pre[i]],mmap[cur[i]]);
                    degree[mmap[cur[i]]]++;
                    break;
                }
            }
        }
        pre=cur;

    }
    vector<string> ans; 
    //不可以直接写一个stirng，这样就退化成一个字典序了度，应该再加个深
    //不加深度才是拓扑排序，
    set<pair<int,string>> sset;
    for(int i=1;i<node_index;i++)
    {
        // cout<<anti_mmap[i]<<" "<<degree[i]<<endl;
        if(degree[i]==0){
            sset.emplace(make_pair(0,anti_mmap[i]));
        }
    }
    while(sset.size())
    {
        auto ttop=*(sset.begin());
        sset.erase(sset.begin());

        ans.push_back(ttop.second);
        for(int i=head[mmap[ttop.second]];i!=-1;i=net[i])
        {
            degree[e[i]]--;
            if(degree[e[i]]==0)
            {
                sset.insert(make_pair(0,anti_mmap[e[i]]));
            }
        }
    }
    if(ans.size()!=node_index-1){
        cout<<"Wrong"<<endl;
    }

    for(int i=0;i<ans.size();i++)
    {
        if(i==ans.size()-1)
            cout<<ans[i];
        else
            cout<<ans[i]<<'.';

    }
    return 0;
}