bzoj 3144: [Hnoi2013]切糕 最小割

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define MAXN 50
#define MAXH 50
#define MAXE MAXV*10
#define MAXV MAXN*MAXN*MAXH
#define INF 0x3f3f3f3f
const int mov[4][2]={{0,1},{1,0},{-1,0},{0,-1}};
struct Edge
{
        int np,val;
        Edge *next,*neg;
}E[MAXE],*V[MAXV];
int sour,sink=1;
int tope=-1;
void addedge(int x,int y,int z)
{
//        printf("Add:%d %d %d\n",x,y,z);
        E[++tope].np=y;
        E[tope].val=z;
        E[tope].next=V[x];
        V[x]=&E[tope];

        E[++tope].np=x;
        E[tope].val=0;
        E[tope].next=V[y];
        V[y]=&E[tope];

        V[x]->neg=V[y];
        V[y]->neg=V[x];
}
int q[MAXV];
int vis[MAXV],bfstime=0;
int lev[MAXV];
int bfs()
{
        int head=-1,tail=0;
        Edge *ne;
        int now;
        q[0]=sour;
        vis[sour]=++bfstime;
        while (head<tail)
        {
                now=q[++head];
                for (ne=V[now];ne;ne=ne->next)
                {
                        if (!ne->val || vis[ne->np]==bfstime)continue;
                        vis[ne->np]=bfstime;
                        q[++tail]=ne->np;
                        lev[ne->np]=lev[now]+1;
                }
        }
        return vis[sink]==bfstime;
}
int dfs(int now,int maxf)
{
        int t,ret=0;
        if (now==sink)return maxf;
        Edge *ne;
        for (ne=V[now];maxf && ne;ne=ne->next)
        {
                if (!ne->val || lev[ne->np]!=lev[now]+1)continue;
                t=dfs(ne->np,min(maxf,ne->val));
                ne->val-=t;
                ne->neg->val+=t;
                maxf-=t;
                ret+=t;
        }
        if (maxf)lev[now]=-1;
        return ret;
}
int dinic()
{
        int ret=0;
        while (bfs())
        {
                ret+=dfs(sour,INF);
        }
        return ret;
}
int n,m,h;
int gid(int x,int y,int z)
{
        return 2+x*m+y+z*m*n;
}
int a[MAXN][MAXN][MAXH];
int main()
{
        freopen("input.txt","r",stdin);
        int i,j,k,k2,x,y,z;
        scanf("%d%d%d",&n,&m,&h);
        int d;
        scanf("%d",&d);
        for (k=1;k<=h;k++)
                for (i=1;i<=n;i++)
                        for (j=1;j<=m;j++)
                                {
                                        scanf("%d",&a[i][j][k]);
                                        addedge(gid(i,j,k-1),gid(i,j,k),a[i][j][k]);
                                }
        for (i=1;i<=n;i++)
                for (j=1;j<=m;j++)
                        for (k=1;k+d<=h;k++)
                                for (k2=0;k2<4;k2++)
                                        if (i+mov[k2][0]>0 && i+mov[k2][0]<=n && j+mov[k2][1]>0 && j+mov[k2][1]<=m)
                                        {
                                        //        addedge(gid(i,j,k),gid(i+mov[k2][0],j+mov[k2][1],k+d),INF);
                                                addedge(gid(i,j,k+d),gid(i+mov[k2][0],j+mov[k2][1],k),INF);
                                        }
        for (i=1;i<=n;i++)
                for (j=1;j<=m;j++)
                {
                        addedge(sour,gid(i,j,0),INF);
                        addedge(gid(i,j,h),sink,INF);
                }
        printf("%d\n",dinic());
}