test_seq......

> #include<iostream>
> #include<cstdio>
> using namespace std;
> 
> int v,e,seqi,ei;
> bool end;
> int from[2000000],to[2000000];
> int map[30][30],seq[30],mark[30];
> 
> bool init()
> {
>     char t,q;
>     ei=0;
>     end=false;
>     memset(map,0,sizeof(map));
>     for(int i=0;i<e;i++)
>     {
>         cin>>t>>q>>q;
>         from[ei]=t-'A';
>         to[ei]=q-'A';
>         ei++;
>     }
>     return true;
> }
> bool dfs(int pos)
> {
>     if(mark[pos]==1)
>     {
>         end=true;
>         return end;
>     }
>     else if(mark[pos]==0)
>     {
>         mark[pos]=1;
>         for(int i=0;i<v;i++)
>             if(map[pos][i] && mark[i]!=-1)
>                 if(dfs(i))
>                     break;
>     }
>     mark[pos]=-1;
>     seqi--;
>     seq[seqi]=pos;
>     return end;
> }
> void test_seq(int t)
> {
>     int i;
>     for(i=0;i<v-1;i++)
>         if(!map[i][i+1])
>             break;
>     if(i==v-1)
>     {
>         end=true;
>         printf("Sorted sequence determined after ");
>         printf("%d relations: ",t+1);
>         for(int j=0;j<v;j++)
>             printf("%c",(char)(seq[j]+'A'));
>         printf(".\n");
>     }
> }
> void toposort(int t)
> {
>     int i;
>     seqi=v;
>     memset(mark,0,sizeof(mark));
>     for(i=0;i<v;i++)
>         if(mark[i]==0)
>             if(dfs(i))
>                 break;
>     if(i<v)
>     {
>         printf("Inconsistency found after %d relations.\n",t+1);
>         return ;
>     }
>     test_seq(t);
> }
> void solve()
> {
>     int i;
>     for(i=0;i<ei && !end;i++)
>     {
>         map[from[i]][to[i]]=1;
>         toposort(i);
>     }
>     if(!end)
>         printf("Sorted sequence cannot be determined.\n");
> }
> int main()
> {
>     while(scanf("%d%d",&v,&e),v)
>     {
>         init();
>         solve();
>     }
>     system("pause");
>     return 0;
> }