2 2
3 2
1 4

1.50

#include<iostream>
#include<cstdio>
#include<cstring>
#include<queue>
using namespace std;
const int N=1000,M=N*N,inf=1e9+7;
int n,m,a[N][N],id[N][N],cnt=1,p[M],tot,s,t;
int dis[M];
bool vis[M],in[M];
queue<int>q;
struct edge{int to,nex,val,cos;}e[M<<1];
void add(int u,int v,int lim,int cos){e[++cnt]=(edge){v,p[u],lim,cos};p[u]=cnt;e[++cnt]=(edge){u,p[v],0,-cos};p[v]=cnt;
}
bool spfa(){for(int i=0;i<M;++i)dis[i]=inf;while(!q.empty())q.pop();memset(in,0,sizeof in);dis[s]=0;q.push(s);while(!q.empty()){int x=q.front();q.pop();in[x]=0;for(int i=p[x];i;i=e[i].nex){int v=e[i].to;if(e[i].val&&dis[v]>dis[x]+e[i].cos){dis[v]=dis[x]+e[i].cos;if(!in[v]){q.push(v);in[v]=1;}}}}return dis[t]<inf;
}
int dfs(int x,int li){vis[x]=1;if(x==t)return li;int use=li;for(int i=p[x];i;i=e[i].nex){int v=e[i].to;if(!vis[v]&&e[i].val&&use&&dis[v]==dis[x]+e[i].cos){int re=dfs(v,min(use,e[i].val));use-=re;e[i].val-=re;e[i^1].val+=re;}}return li-use;
}
int dinic(){int ans=0;while(spfa()){memset(vis,0,sizeof(vis));ans+=dfs(s,inf)*dis[t];
//        cout<<ans<<endl;
    }    return ans;
}
int main(){scanf("%d%d",&m,&n);//技术人员数和顾客数tot=n;for(int i=1;i<=n;++i)for(int j=1;j<=m;++j){scanf("%d",&a[i][j]);//第i辆车第m个人修耗时 id[j][i]=++tot;}t=++tot;for(int i=1;i<=n;++i)//第i辆车 for(int j=1;j<=m;++j)//第m个人 for(int k=1;k<=n;++k)//倒数第k个修 add(i,id[j][k],1,k*a[i][j]);for(int i=1;i<=n;++i)add(s,i,1,0);for(int j=1;j<=m;++j)for(int k=1;k<=n;++k){add(id[j][k],t,1,0);}double ave=dinic();ave/=n;printf("%.2f",ave);return 0;
}

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstdlib>
#include<cstring>
#include<vector>
#include<queue>
#define ll long long
using namespace std;
const int INT=1e7;
const int maxn=4000;
inline int read(){int an=0;char ch=getchar();while('9'<ch||ch<'0'){ch=getchar();}while(ch<='9'&&'0'<=ch){an=an*10+(ch^48);ch=getchar();}return an;
}
double ANS;
int f[40000],id[100][100],cnt=1,S,T,cntt,n,m;
int map[100][100],car_id[100];
struct saber{
int nex,to,wi,lim;
}b[maxn*maxn];
inline void add2(int x,int y,int z,int wi){cnt++;b[cnt].nex=f[x];b[cnt].to=y;b[cnt].wi=wi;b[cnt].lim=z;f[x]=cnt;
}
inline void add(int x,int y,int z,int wi){add2(x,y,z,wi);add2(y,x,0,-wi);
}
inline void prepare(){m=read();n=read();//m个mmp的工人,闲着没事儿去~~修~~ (开)n个车for(int i=1;i<=n;i++)for(int j=1;j<=m;j++)cntt++,id[i][j]=cntt;for(int j=1;j<=n;j++)cntt++,car_id[j]=cntt;cntt++;S=cntt;cntt++;T=cntt;for(int i=1;i<=n;i++)for(int j=1;j<=m;j++)map[i] [j]=read();//前是车号,后是人修 for(int i=1;i<=n;i++)//n车 for(int j=1;j<=m;j++)for(int k=1;k<=n;k++)add( car_id[i] , id[k][j] ,1, k*map [i] [j] );for(int i=1;i<=n;i++)add(S,car_id[i],1,0);for(int i=1;i<=n;i++)//n车 for(int j=1;j<=m;j++)add(id[i][j],T,1,0);
}
deque<int>q;
int dis[maxn];
bool in[maxn],vis[maxn];
inline int bfs(){while(!q.empty())q.pop_back();for(int i=0;i<=cntt+233;i++)dis[i]=INT;dis[S]=0;q.push_back(S);memset(in,0,sizeof in);while(!q.empty()){int x=q.front();q.pop_front();in[x]=0;for(int i=f[x];i;i=b[i].nex){int v=b[i].to;if(dis[v]>dis[x]+b[i].wi&&b[i].lim){dis[v]=dis[x]+b[i].wi;if(!in[v]){in[v]=1;if(!q.empty()&&dis[q.front()]>dis[v])q.push_front(v);else q.push_back(v);}}}}return dis[T]!=INT;
}
inline int dfs(int x,int li){int used=li;vis[x]=1;if(x==T||!li)return li;for(int i=f[x];i&&used;i=b[i].nex){int v=b[i].to;if(vis[v])continue;if(dis[v]==dis[x]+b[i].wi&&b[i].lim){int re=dfs(v,min(used,b[i].lim));used-=re;b[i^1].lim+=re;b[i].lim-=re;}}return li-used;
}
inline void dinic(){int ans=0;while(bfs()){memset(vis,0,sizeof vis);ans+=dis[T]*dfs(S,INT);}ANS=(double)ans/(double)n;printf("%0.2f",ANS);
}
int main(){prepare();dinic();return 0;
}