2007Amber国家队论文

  1 /*by SilverN*/
  2 #include<algorithm>
  3 #include<iostream>
  4 #include<cstring>
  5 #include<cstdio>
  6 #include<cmath>
  7 #include<vector>
  8 #include<queue>
  9 using namespace std;
 10 const int INF=0x3f3f3f3f;
 11 const int mxn=100010;
 12 const int mx[5]={0,1,0,-1,0};
 13 const int my[5]={0,0,1,0,-1};
 14 int read(){
 15     int x=0,f=1;char ch=getchar();
 16     while(ch<'0' || ch>'9'){if(ch=='-')f=-1;ch=getchar();}
 17     while(ch>='0' && ch<='9'){x=x*10+ch-'0';ch=getchar();}
 18     return x*f;
 19 }
 20 struct edge{
 21     int v,nxt,f;
 22 }e[mxn<<1];
 23 int hd[mxn],mct=1;
 24 void add_edge(int u,int v,int w){
 25     e[++mct].v=v;e[mct].nxt=hd[u];e[mct].f=w; hd[u]=mct;return;
 26 }
 27 void insert(int u,int v,int w){
 28     add_edge(u,v,w);add_edge(v,u,0);return;
 29 }
 30 queue<int>q;
 31 int d[mxn];
 32 int n,m,S,T;
 33 bool BFS(){
 34     memset(d,0,sizeof d);
 35     d[S]=1;
 36     q.push(S);
 37     while(!q.empty()){
 38         int u=q.front();q.pop();
 39         for(int i=hd[u];i;i=e[i].nxt){
 40             int v=e[i].v;
 41             if(e[i].f && !d[v]){
 42                 d[v]=d[u]+1;
 43                 q.push(v);
 44             }
 45         }
 46     }
 47     return d[T];
 48 }
 49 int DFS(int u,int lim){
 50     if(u==T)return lim;
 51     int f=0,tmp;
 52     for(int i=hd[u],v;i;i=e[i].nxt){
 53         v=e[i].v;
 54         if(d[v]==d[u]+1 && e[i].f && (tmp=DFS(v,min(lim,e[i].f)))){
 55             e[i].f-=tmp;  e[i^1].f+=tmp;
 56             lim-=tmp;   f+=tmp;
 57             if(!lim)return f;
 58         }
 59     }
 60     d[u]=0;
 61     return f;
 62 }
 63 int Dinic(){
 64     int res=0;
 65     while(BFS())res+=DFS(S,0x3f3f3f3f);
 66     return res;
 67 }
 68 int id[120][120];
 69 int mp[120][120];
 70 int smm=0,dt=0;
 71 void solve(){
 72     int i,j;
 73     for(i=1;i<=n;i++)
 74         for(j=1;j<=m;j++)
 75             id[i][j]=++dt;
 76     S=0;T=dt+1;
 77     for(i=1;i<=n;i++)
 78         for(j=1;j<=m;j++){
 79             if((i+j)&1){
 80                 insert(S,id[i][j],mp[i][j]);
 81                 for(int k=1;k<=4;k++){
 82                     int nx=i+mx[k],ny=j+my[k];
 83                     if(nx>0 && nx<=n && ny>0 && ny<=m)
 84                         insert(id[i][j],id[nx][ny],INF);
 85
 86                 }
 87             }
 88             else insert(id[i][j],T,mp[i][j]);
 89         }
 90     return;
 91 }
 92 int main(){
 93     int i,j;
 94     n=read();m=read();
 95     for(i=1;i<=n;i++)
 96         for(j=1;j<=m;j++){
 97             mp[i][j]=read();
 98             smm+=mp[i][j];
 99         }
100     solve();
101     int res=Dinic();
102 //  printf("Res:%d\n",res);
103     printf("%d\n",smm-res);
104     return 0;
105 }