POJ 1364 King 差分约束 SPFA

终于用SPFA AC了~~这题还真是！！稍后要把差分约束和SPFA总结一下~~，觉得这题还是挺有意思的。具体为什么WA了呢？？？ 不是那么清楚~~ 照着做就是AC了。发现形成链表就那么简单~ 嘿嘿~

#include<iostream>
#include<queue>
#define MAXN 103
#define INF 0x7F7F7F7F
using namespace std;

struct Node
{
       int v,price;
       Node *next;
}Edge[MAXN],*ptr[MAXN];


int N,M;
int edgeNum;

void addEdge( int u,int v,int val )
{
     Node *p=&Edge[edgeNum++];
     
     p->v=v;
     p->price=val;
     p->next=ptr[u];
     ptr[u]=p;
}

bool spfa()
{
     bool used[MAXN];
     int dist[MAXN],cnt[MAXN];
     queue<int>myQueue;
     memset( used,true,sizeof(used) );
     memset( dist,0,sizeof(dist) );
     memset( cnt,0,sizeof(cnt) );
     
     for( int i=0;i<=N;i++ ) 
          myQueue.push(i);
     
     while( !myQueue.empty() )
     {
            int u=myQueue.front();myQueue.pop();
            used[u]=false;
            Node *p=ptr[u];
            while( p )
            {
                   if( dist[p->v]>dist[u]+p->price )
                   {
                       dist[p->v]=dist[u]+p->price;
                       if( !used[p->v] )
                       {
                           myQueue.push(p->v);
                           used[p->v]=true;
                           if( ++cnt[p->v]>N )
                               return false;
                       }
                   }
                   p=p->next;
            }
     }
     return true;
}

int main()
{
    while( scanf( "%d",&N )!=EOF )
    {
           edgeNum=0;
           if( N==0 )
               break;
           scanf( "%d",&M );
           int i,j,k;
           char com[3];
           int a,b,p;
           for( i=0;i<=N;i++ ) ptr[i]=NULL;
           
           for( i=1;i<=M;i++ )
           {
                scanf( "%d %d %s %d",&a,&b,&com,&p );
                if( com[0]=='g' )
                    addEdge( a+b,a-1,-p-1 );
                else
                    addEdge( a-1,a+b,p-1 );
           }
           if( !spfa() )
               printf( "successful conspiracy\n" );
           else
               printf( "lamentable kingdom\n" ); 
    }
    return 0;
}