题目：http://www.lydsy.com/JudgeOnline/problem.php?id=3144
把每一条z轴都拿出来，s->(x,y,1),c=f[x][y][1];(x,y,k)->(x,y,k+1),c=f[x][y][k];(x,y,r)->t,c=inf
然后对于四联通的点，(x,y,z)->(x',y’,z-d)
似乎这叫经典的最小割模型？
#include<cstring> #include<cstdio> #include<algorithm> #include<cmath> #include<iostream> #include<queue> #define rep(i,l,r) for (int i=l;i<=r;i++) #define down(i,l,r) for (int i=l;i>=r;i--) #define clr(x,y) memset(x,y,sizeof(x)) #define maxn 100050 #define ll long long #define inf int(1e9) #define eps 1e-6 using namespace std; struct data{int obj,pre,c; }e[1000500]; int n,tot=1,m,r,t,d,f[45][45][45],uu[maxn]; int head[maxn],cur[maxn],dx[4]={0,1,0,-1},dy[4]={1,0,-1,0}; int read(){int x=0,f=1; char ch=getchar();while (!isdigit(ch)) {if (ch=='-') f=-1; ch=getchar();}while (isdigit(ch)) {x=x*10+ch-'0'; ch=getchar();}return x*f; } int p(int x,int y,int z){if (z==0) return 0;return (z-1)*n*m+(x-1)*m+y; } void insert(int x,int y,int z){e[++tot].obj=y; e[tot].pre=head[x]; e[tot].c=z; head[x]=tot;e[++tot].obj=x; e[tot].pre=head[y]; e[tot].c=0; head[y]=tot; } bool jud(int x,int y){if (x<1||y<1||x>n||y>m) return 0;return 1; } void build(){rep(i,1,n) rep(j,1,m){rep(k,1,r) insert(p(i,j,k-1),p(i,j,k),f[i][j][k]); insert(p(i,j,r),t,inf);rep(k,0,3){int x=i+dx[k],y=j+dy[k];if (jud(x,y)) rep(o,d+1,r) insert(p(i,j,o),p(x,y,o-d),inf);}} } bool bfs(){queue<int >q;clr(uu,-1); q.push(0); uu[0]=0; while (!q.empty()){int u=q.front(); q.pop();for (int j=head[u];j;j=e[j].pre){int v=e[j].obj;if (uu[v]==-1&&e[j].c){uu[v]=uu[u]+1;q.push(v);}}}if (uu[t]==-1) return 0;return 1; } int dfs(int x,int mx){if (x==t) return mx;int used=0;for (int j=cur[x];j;j=e[j].pre){int v=e[j].obj;if (uu[v]==uu[x]+1){int w=dfs(v,min(e[j].c,mx-used));used+=w; e[j].c-=w; e[j^1].c+=w;if (e[j].c) cur[x]=j;if (used==mx) return mx; }}if (!used) uu[x]=-1;return used; } int dinic(){int ans=0;while (bfs()){rep(i,0,t) cur[i]=head[i];ans+=dfs(0,inf);}return ans; } int main(){n=read(); m=read(); r=read(); t=n*m*r+1;d=read();rep(i,1,r)rep(j,1,n) rep(k,1,m) f[j][k][i]=read();build();printf("%d\n",dinic()); return 0; }
