最大点权独立集，参见胡伯涛论文
#include <iostream>
#include <cstring>
#include <cstdio>
#include <queue>
using namespace std;
int m, n, a[105][105], hea[10005], ss, tt, tot, maxFlow, lev[10005], cnt;
const int oo=0x3f3f3f3f;
const int dx[]={0, 1, 0, -1, 0};
const int dy[]={0, 0, 1, 0, -1};
queue<int> d;
struct Edge{
int too, nxt, val;
}edge[100005];
inline int f(int x, int y){
return n*(x-1)+y;
}
void add_edge(int fro, int too, int val){
edge[cnt].nxt = hea[fro];
edge[cnt].too = too;
edge[cnt].val = val;
hea[fro] = cnt++;
}
void addEdge(int fro, int too, int val){
add_edge(fro, too, val);
add_edge(too, fro, 0);
}
bool bfs(){
memset(lev, 0, sizeof(lev));
lev[ss] = 1;
d.push(ss);
while(!d.empty()){
int x=d.front();
d.pop();
for(int i=hea[x]; i!=-1; i=edge[i].nxt){
int t=edge[i].too;
if(!lev[t] && edge[i].val>0){
lev[t] = lev[x] + 1;
d.push(t);
}
}
}
return lev[tt]!=0;
}
int dfs(int x, int lim){
if(x==tt) return lim;
int addFlow=0;
for(int i=hea[x]; i!=-1 && addFlow<lim; i=edge[i].nxt){
int t=edge[i].too;
if(lev[t]==lev[x]+1 && edge[i].val>0){
int tmp=dfs(t, min(lim-addFlow, edge[i].val));
edge[i].val -= tmp;
edge[i^1].val += tmp;
addFlow += tmp;
}
}
return addFlow;
}
void dinic(){
while(bfs()) maxFlow += dfs(ss, oo);
}
int main(){
memset(hea, -1, sizeof(hea));
cin>>m>>n;
ss = 0; tt = m * n + 1;
for(int i=1; i<=m; i++)
for(int j=1; j<=n; j++)
scanf("%d", &a[i][j]);
for(int i=1; i<=m; i++)
for(int j=1; j<=n; j++){
tot += a[i][j];
if((i+j)&1) addEdge(ss, f(i,j), a[i][j]);
else addEdge(f(i,j), tt, a[i][j]);
for(int k=1; k<=4; k++){
int tx=i+dx[k];
int ty=j+dy[k];
if(tx<1 || tx>m || ty<1 || ty>n) continue;
if((i+j)&1) addEdge(f(i,j), f(tx,ty), oo);
else addEdge(f(tx,ty), f(i,j), oo);
}
}
dinic();
cout<<tot-maxFlow<<endl;
return 0;
}