Bellman_Ford

//-----------Bellman_Ford------------
struct Edge
{
int v,u;
int weight;
}edge[M];
int dist[N];

bool Bellman_Ford(int n,int m,int s)
{
int i,j;
bool flag;
for(i=1;i<=n;i++)
        dist[i]=MAXVAL;
    dist[s]=0;

for(i=1;i<n;i++)
    {
        flag=false;
for(j=0;j<m;j++)
        {
if(dist[edge[j].v]+edge[j].weight<dist[edge[j].u])
                dist[edge[j].u]=dist[edge[j].v]+edge[j].weight,flag=true;
        }
if(flag==false)    return true;
    }///显然写的是单向的!
    for(j=0;j<m;j++)
    {
if(dist[edge[j].v]+edge[j].weight<dist[edge[j].u])
return false;
    }

return true;
}

写的不对或不好的地方，请大虾多多指教!    ——Never