http://www.lydsy.com/JudgeOnline/problem.php?id=3144
如果D=2 ，两个点，高度为4，建图如下
#include<queue> #include<cstdio> #include<cstring> #include<iostream> #include<algorithm> using namespace std; #define N 64005 #define M 323205 const int inf=2e9; int n; int P,Q,R,D; int cost[41][41][41]; int tot=1; int front[N],nxt[M<<1],to[M<<1],val[M<<1],from[M<<1]; int lev[N],num[N]; int path[N]; int cur[N]; int src,decc; int dx[4]={-1,0,1,0}; int dy[4]={0,1,0,-1}; void read(int &x) { x=0; char c=getchar(); while(!isdigit(c)) c=getchar(); while(isdigit(c)) { x=x*10+c-'0'; c=getchar(); } } void add(int u,int v,int w) { to[++tot]=v; nxt[tot]=front[u]; front[u]=tot; from[tot]=u; val[tot]=w; to[++tot]=u; nxt[tot]=front[v]; front[v]=tot; from[tot]=v; val[tot]=0; // cout<<u<<' '<<v<<' '<<w<<'\n'; } bool bfs() { queue<int>q; for(int i=src;i<=decc;++i) lev[i]=decc; q.push(decc); lev[decc]=0; int now,t; while(!q.empty()) { now=q.front(); q.pop(); for(int i=front[now];i;i=nxt[i]) { t=to[i]; if(lev[t]==decc && val[i^1]) { lev[t]=lev[now]+1; q.push(t); } } } return lev[src]!=decc; } int augment() { int now=decc,flow=inf; int i; while(now!=src) { i=path[now]; flow=min(flow,val[i]); now=from[i]; } now=decc; while(now!=src) { i=path[now]; val[i]-=flow; val[i^1]+=flow; now=from[i]; } return flow; } int isap() { int flow=0; if(!bfs()) return 0; memset(num,0,sizeof(num)); for(int i=src;i<=decc;++i) num[lev[i]]++,cur[i]=front[i]; int now=src,t; while(lev[src]<=decc) { if(now==decc) { flow+=augment(); now=src; } bool advanced=false; for(int i=cur[now];i;i=nxt[i]) { t=to[i]; if(lev[t]==lev[now]-1 && val[i]) { advanced=true; path[t]=i; cur[now]=i; now=t; break; } } if(!advanced) { int mi=decc; for(int i=front[now];i;i=nxt[i]) if(val[i]) mi=min(mi,lev[to[i]]); if(!--num[lev[now]]) break; num[lev[now]=mi+1]++; cur[now]=front[now]; if(now!=src) now=from[path[now]]; } } return flow; } int turn(int i,int j,int k) { return ((i-1)*Q+j-1)*(R+1)+k; } void build() { int nx,ny; for(int i=1;i<=P;++i) for(int j=1;j<=Q;++j) for(int k=1;k<=R;++k) { add(turn(i,j,k),turn(i,j,k+1),cost[i][j][k]); if(k>D) { for(int d=0;d<4;++d) { nx=i+dx[d]; ny=j+dy[d]; if(nx>=1 && nx<=P && ny>=1 && ny<=Q) add(turn(i,j,k),turn(nx,ny,k-D),inf); } } } decc=P*Q*(R+1)+1; for(int i=1;i<=P;++i) for(int j=1;j<=Q;++j) { add(src,turn(i,j,1),inf); add(turn(i,j,R+1),decc,inf); } } int main() { freopen("nutcake.in","r",stdin); freopen("nutcake.out","w",stdout); read(P); read(Q); read(R); read(D); for(int i=1;i<=R;++i) for(int j=1;j<=P;++j) for(int k=1;k<=Q;++k) { read(cost[j][k][i]); // cout<<j<<' '<<k<<' '<<i<<' '<<cost[j][k][i]<<'\n'; } build(); cout<<isap(); }
2018.3.20 考试代码
#include<queue> #include<cstdio> #include<iostream> using namespace std; const int inf=2e9; #define M 400000 #define N 70000 int P,Q,R,D; int a[41][41][41]; int front[N],nxt[M<<1],to[M<<1],cap[M<<1],tot=1; int src,decc; int lev[N],cur[N]; queue<int>q; void read(int &x) { x=0; char c=getchar(); while(!isdigit(c)) c=getchar(); while(isdigit(c)) { x=x*10+c-'0'; c=getchar(); } } void init() { read(P); read(Q); read(R); read(D); for(int i=1;i<=R;++i) for(int j=1;j<=P;++j) for(int k=1;k<=Q;++k) read(a[i][j][k]); } int turn(int i,int j,int k) { return ((i-1)*Q+j-1)*(R+1)+k; } void add(int u,int v,int val) { to[++tot]=v; nxt[tot]=front[u]; front[u]=tot; cap[tot]=val; to[++tot]=u; nxt[tot]=front[v]; front[v]=tot; cap[tot]=0; } void build() { decc=(R+1)*P*Q+1; for(int i=1;i<=P;++i) for(int j=1;j<=Q;++j) { add(src,turn(i,j,1),inf); for(int k=1;k<=R;++k) add(turn(i,j,k),turn(i,j,k+1),a[k][i][j]); add(turn(i,j,R+1),decc,inf); } for(int i=1;i<=P;++i) for(int j=1;j<=Q;++j) for(int k=D+2;k<=R+1;++k) { if(i>1) add(turn(i,j,k),turn(i-1,j,k-D),inf); if(i<P) add(turn(i,j,k),turn(i+1,j,k-D),inf); if(j>1) add(turn(i,j,k),turn(i,j-1,k-D),inf); if(j<Q) add(turn(i,j,k),turn(i,j+1,k-D),inf); } } bool bfs() { for(int i=src;i<=decc;++i) lev[i]=-1,cur[i]=front[i]; while(!q.empty()) q.pop(); q.push(src); lev[src]=0; int now; while(!q.empty()) { now=q.front(); q.pop(); for(int i=front[now];i;i=nxt[i]) if(lev[to[i]]==-1 && cap[i]) { lev[to[i]]=lev[now]+1; if(to[i]==decc) return true; q.push(to[i]); } } return false; } int dinic(int now,int flow) { if(now==decc) return flow; int delta,rest=0; for(int &i=cur[now];i;i=nxt[i]) if(lev[to[i]]==lev[now]+1 && cap[i]) { delta=dinic(to[i],min(flow-rest,cap[i])); if(delta) { rest+=delta; cap[i]-=delta; cap[i^1]+=delta; if(rest==flow) break; } } if(rest!=flow) lev[now]=-1; return rest; } void solve() { int ans=0; while(bfs()) ans+=dinic(src,inf); printf("%d",ans); } int main() { freopen("cake.in","r",stdin); freopen("cake.out","w",stdout); init(); build(); solve(); }