poj 1364 King(差分约束)

题目：http://poj.org/problem?id=1364

 #include <iostream>
 #include <cstdio>
 #include <cstring>
 #include <algorithm>
 using namespace std;

 const int INF=(<<);
 int n,m,d[];
 struct node
 {
     int u,v,w;
 }edge[];

 bool bellman_ford()
 {
     int i,j;
     memset(d,,sizeof(d));
     for(i=; i<n; i++)
     {
         for(j=; j<m; j++)
         if(d[edge[j].u]+edge[j].w<d[edge[j].v])
         d[edge[j].v]=d[edge[j].u]+edge[j].w;
     }
     for(j=; j<m; j++)
         if(d[edge[j].u]+edge[j].w<d[edge[j].v])
         return false;
     return true;
 }

 int main()
 {
     int a,b,c,i;
     char s[];
     while(~scanf("%d",&n)&&n)
     {
         scanf("%d",&m);
         for(i=; i<m; i++)
         {
             scanf("%d%d%s%d",&a,&b,s,&c);
             if(s[]=='g')
             {
                 edge[i].u=a+b;
                 edge[i].v=a-;
                 edge[i].w=-c-;
             }
             else
             {
                 edge[i].u=a-;
                 edge[i].v=a+b;
                 edge[i].w=c-;
             }
         }
         if(bellman_ford())
         printf("lamentable kingdom\n");
         else
         printf("successful conspiracy\n");
     }
     return ;
 }

参考博客：http://blog.csdn.net/wangjian8006/article/details/7956848