[bzoj2055]80人环游世界[网络流，上下界网络流]

  1 #include <bits/stdc++.h>
  2 
  3 #define    INF    0x3f3f3f3f
  4 
  5 using namespace std;
  6 
  7 template<const int _n,const int _m>
  8 struct    Edge
  9 {
 10     struct Edge_base { int    to,next,w,c; }e[_m]; int    cnt,p[_n];
 11     Edge() { clear(); }
 12     void    clear() { cnt=1,memset(p,0,sizeof(p)); }
 13     void    insert(const int x,const int y,const int z,const int zz)
 14     { e[++cnt].to=y; e[cnt].next=p[x]; e[cnt].w=z; e[cnt].c=zz; p[x]=cnt; return ; }
 15     void    link(const int x,const int y,const int z,const int zz)
 16     { insert(x,y,z,zz); insert(y,x,0,-zz); }
 17     int    start(const int x) { return p[x]; }
 18     Edge_base& operator[](const int x) { return e[x]; }
 19 };
 20 
 21 int    n,m,Dis[210],Cost;
 22 int    cur[210],SSS,TTT,SS,TT;
 23 bool    visited[210];
 24 Edge<210,510000>e;
 25 
 26 bool    Spfa(const int S)
 27 {
 28     int    i,t,temp;
 29     queue<int>    Q;
 30     memset(Dis,0x3f,sizeof(Dis));
 31     Dis[S]=0;
 32     visited[S]=true;
 33     Q.push(S);
 34     while(!Q.empty())
 35     {
 36         t=Q.front(),Q.pop();
 37         visited[t]=false;
 38         for(i=e.start(t);i;i=e[i].next)
 39         {
 40             temp=e[i].to;
 41             if(e[i].w && Dis[t]+e[i].c<Dis[temp])
 42             {
 43                 Dis[temp]=Dis[t]+e[i].c;
 44                 if(!visited[temp])
 45                 {
 46                     visited[temp]=true;
 47                     Q.push(temp);
 48                 }
 49             }
 50         }
 51     }
 52     return Dis[TTT]!=0x3f3f3f3f;
 53 }
 54 
 55 int    Dfs(const int S,const int bk)
 56 {
 57     if(S==TTT)return bk;
 58     visited[S]=true;
 59     int    rest=bk;
 60     for(int &i=cur[S];i;i=e[i].next)
 61     {
 62         if(!visited[e[i].to] && Dis[S]+e[i].c==Dis[e[i].to] && e[i].w)
 63         {
 64             int    flow=Dfs(e[i].to,min(rest,e[i].w));
 65             Cost+=flow*e[i].c;
 66             e[i].w-=flow;
 67             e[i^1].w+=flow;
 68             if((rest-=flow)<=0)break;
 69         }
 70     }
 71     if(bk==rest)Dis[S]=0x3f3f3f3f;
 72     visited[S]=false;
 73     return bk-rest;
 74 }
 75 
 76 int    Zkw()
 77 {
 78     int    Flow=0;
 79     while(Spfa(SSS))
 80     {
 81         memcpy(cur,e.p,sizeof(cur));
 82         Flow+=Dfs(SSS,0x3f3f3f3f);
 83     }
 84     return Cost;
 85 }
 86 
 87 int main()
 88 {
 89     int    i,j,a,x;
 90 
 91     scanf("%d%d",&n,&m);
 92 
 93     SS=n<<1|1,TT=SS+1,SSS=TT+1,TTT=SSS+1;
 94     for(i=1;i<=n;++i)
 95     {
 96         scanf("%d",&a);
 97         e.link(SSS,i+n,a,0);
 98         e.link(i,TTT,a,0);
 99         e.link(i+n,TT,INF,0);
100         e.link(SS,i,INF,0);
101     }
102     
103     for(i=1;i<=n;++i)for(j=i+1;j<=n;++j)
104     {
105         scanf("%d",&x);
106         if(x==-1)continue;
107         e.link(i+n,j,INF,x);
108     }
109 
110     e.link(TT,SS,m,0);
111 
112     printf("%d\n",Zkw());
113     return 0;
114 }