分析
显然要求的是最小割啊qwq
建出图跑一遍Dinic就行了qwq
然而我加上当前弧优化后,跑得比不加还慢
代码
//It is made by M_sea
#include <algorithm>
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <queue>
#define re register
using namespace std;
inline int read() {
int X=0,w=1; char c=getchar();
while (c<'0'||c>'9') { if (c=='-') w=-1; c=getchar(); }
while (c>='0'&&c<='9') X=X*10+c-'0',c=getchar();
return X*w;
}
const int MAXN=1000000+10;
const int INF=2147483647;
struct Edge { int v,w,nxt; };
Edge e[MAXN*6];
int head[MAXN],cnt=0;
int cur[MAXN];
inline void addEdge(int u,int v,int c) {
e[cnt].v=v,e[cnt].w=c,e[cnt].nxt=head[u],head[u]=cnt++;
e[cnt].v=u,e[cnt].w=c,e[cnt].nxt=head[v],head[v]=cnt++;
}
int level[MAXN];
int n,m,s,t;
inline int Dinic_Bfs() {
memset(level,0,sizeof(level));
queue<int> Q; Q.push(s); level[s]=1;
while (!Q.empty()) {
int u=Q.front(); Q.pop();
for (re int i=head[u];i!=-1;i=e[i].nxt) {
int v=e[i].v;
if (!level[v]&&e[i].w) {
level[v]=level[u]+1;
Q.push(v);
}
}
}
return level[t];
}
inline int Dinic_Dfs(int u,int cpflow) {
if (u==t) return cpflow;
int addflow=0;
for (re int i=head[u];i!=-1&&addflow<cpflow;i=e[i].nxt) {
int v=e[i].v;
if (level[v]==level[u]+1&&e[i].w) {
int tmpadd=Dinic_Dfs(v,min(cpflow-addflow,e[i].w));
e[i].w-=tmpadd; e[i^1].w+=tmpadd;
addflow+=tmpadd;
}
}
if (!addflow) level[u]=0; //玄学优化
return addflow;
}
inline int Dinic() {
int maxflow=0;
while (Dinic_Bfs()) maxflow+=Dinic_Dfs(s,INF);
return maxflow;
}
inline int id(int x,int y) { return m*(x-1)+y; }
int main() {
memset(head,-1,sizeof(head));
n=read(),m=read(),s=1,t=n*m;
for (re int i=1;i<=n;++i)
for (re int j=1;j<m;++j)
addEdge(id(i,j), id(i,j+1), read());
for (re int i=1;i<n;++i)
for (re int j=1;j<=m;++j)
addEdge(id(i,j), id(i+1,j), read());
for (re int i=1;i<n;++i)
for (re int j=1;j<m;++j)
addEdge(id(i,j), id(i+1,j+1), read());
printf("%d\n",Dinic());
return 0;
}
%%%%%%%%%%%%吊打我