【SPFA】POJ3259-Wormhole

普通的SPFA的负环判定。犯了三个错误，全部写在注释里了。

 #include<iostream>
 #include<cstdio>
 #include<cstring>
 #include<queue>
 #include<algorithm>
 using namespace std;
 const int MAXNm=+;
 const int MAXNn=+;
 const int INF=0x7fffffff;
 int n,m,ww;
 int u[MAXNm],v[MAXNm],w[MAXNm];
 int first[MAXNn],next[MAXNm];
 int dis[MAXNn];
 void addedge(int tu,int num)
 {
     next[num]=first[tu];
     first[tu]=num;
 }

 int SPFA()
 {
     queue<int> que;
     int vis[MAXNn],appear[MAXNn];
     que.push();
     for (int i=;i<n;i++)
     {
         dis[i]=INF;
         vis[i]=;
         appear[i]=;
     }
     /*不要遗漏了上述初始化步骤*/
     dis[]=;
     vis[]=;
     appear[]=;

     while (!que.empty())
     {
         int head=que.front();
         que.pop();
         vis[head]=;
         /*注意这里vis[head]要重归于零！很容易错写成vis[k]=0*/
         int k=first[head];
         while (k!=-)
         {
             if (dis[v[k]]>dis[u[k]]+w[k])
             {
                 dis[v[k]]=dis[u[k]]+w[k];
                 if (!vis[v[k]])
                 /*不要把vis[v[k]]写成vis[k]了*/
                 {
                     appear[v[k]]++;
                     vis[v[k]]=;
                     que.push(v[k]);
                 }
                 if (appear[v[k]]>=n) return ;
             }
             k=next[k];
         }
     }
     return ;
 }

 int main()
 {
     int c;
     scanf("%d",&c);
     for (int kase=;kase<c;kase++)
     {
         scanf("%d%d%d",&n,&m,&ww);
         for (int i=;i<n;i++) first[i]=-;

         for (int i=;i<m;i++)
         {
             scanf("%d%d%d",&u[i],&v[i],&w[i]);
             u[i]--;
             v[i]--;
             addedge(u[i],i);
             u[i+m]=v[i];
             v[i+m]=u[i];
             w[i+m]=w[i];
             addedge(u[i+m],i+m);
         }
         for (int i=*m;i<*m+ww;i++)
         {
             scanf("%d%d%d",&u[i],&v[i],&w[i]);
             u[i]--;
             v[i]--;
             w[i]=-w[i];
             addedge(u[i],i);
         }
         if (!SPFA()) cout<<"YES";else cout<<"NO";cout<<endl;
     }

     return ;
 }