hdu1853 km算法

 //hdu1853
 #include<stdio.h>
 #include<string.h>
 #define INF 99999999
 int map[][],pr[],pl[],visr[],visl[],slack[],match[];
 int n,m;
 int dfs(int u)
 {
     int i,j,val;

     visl[u]=;
     for(i=;i<=n;i++)
     {
         if(!visr[i])
         {
             val=pr[i]+pl[u]-map[u][i];
             if(val==)
             {
                 visr[i]=;
                 if(match[i]==-||dfs(match[i]))
                 {
                     match[i]=u;
                     return ;
                 }
             }
             if(val>&&slack[i]>val)
                 slack[i]=val;
         }
     }
     return ;
 }
 void km()
 {
     int i,j,res=,d;
     for(i=;i<=n;i++)
         pl[i]=INF;
     memset(pr,,sizeof(pr));
     memset(match,-,sizeof(match));
     for(i=;i<=n;i++)
     {
         for(j=;j<=n;j++)
             slack[j]=INF;
         while()
         {
             memset(visr,,sizeof(visr));
             memset(visl,,sizeof(visl));
             if(dfs(i))
                 break;
             d=INF;
             for(j=;j<=n;j++)
             {
                 if(!visr[j]&&d>slack[j])
                     d=slack[j];
             }
             for(j=;j<=n;j++)
             {
                 if(visr[j])
                     pr[j]+=d;
                 if(visl[j])
                     pl[j]-=d;
             }
         }
     }
 }
 int main()
 {
     int i,j;
     while(scanf("%d%d",&n,&m)!=EOF)
     {
         for(i=;i<=n;i++)
             for(j=;j<=n;j++)
                 map[i][j]=-INF;

         for(i=;i<m;i++)
         {
             int x,y,z;
             scanf("%d%d%d",&x,&y,&z);
             if(map[x][y]<-z)
             {
                 map[x][y]=-z;
             }
         }
         /*for(i=1;i<=n;i++)
         {
             for(j=1;j<=n;j++)
                 printf("%d ",map[i][j]);
             printf("\n");
         }*/
         km();
         int flag=;
         int res=;
         for(i=;i<=n;i++)
         {
             if(map[match[i]][i]==-INF)
             {flag=;break;}
             else res+=map[match[i]][i];
         }
         if(!flag)printf("-1\n");
         else
          printf("%d\n",-res);
     }
 }