poj 1364

poj 1364

http://acm.pku.edu.cn/JudgeOnline/problem?id=1364
先贴个代码，差分约束，虽然参照别人放入代码过了，但是自己也搞得不是太明白！
慢慢学习！

Source Code

Problem: 1364		User: lovecanon
Memory: 208K		Time: 0MS
Language: C++		Result: Accepted

#include < iostream >
#include < string .h >
using   namespace  std;
struct  node{
     int  u,v,val;
}edge[ 101 ];
int  a,b,va,i,j,n,m,dist[ 101 ];
char  rel[ 3 ];
void  bellman_ford(){
    memset(dist, 0 , sizeof (dist));
     int  flag;
     for (i = 0 ;i <= n;i ++ ){
        flag = 0 ;
         for (j = 1 ;j <= m;j ++ ){
             if (dist[edge[j].u] + edge[j].val < dist[edge[j].v]){ // can de updated
                dist[edge[j].v] = dist[edge[j].u] + edge[j].val;
                flag = 1 ;
            }
        }
         if ( ! flag)  break ;
    }
     if ( ! flag) printf( " lamentable kingdom\n " );
     else  printf( " successful conspiracy\n " );
    
}
int  main(){
     while (scanf( " %d " , & n) && n){
        scanf( " %d " , & m);
         for (i = 1 ;i <= m;i ++ ){
            scanf( " %d%d%s%d " , & a, & b,rel, & va);
             if (rel[ 0 ] == ' l ' ){
                edge[i].u = a + b;
                edge[i].v = a - 1 ; // a-1 not b-1 在这儿错了好多次
                edge[i].val = va - 1 ;
            }
             else {
                edge[i].u = a - 1 ;
                edge[i].v = a + b;
                edge[i].val =- 1 - va;
            }
        }
        bellman_ford();
    }
     return   0 ;
}