题意是啥…….

思路：

不是与1或n连起来的边 边权是1

否则是inf

跑网络流

//By SiriusRen#include 
     
      #include 
      
       #include 
       
        #include 
        
         using namespace std;const int N=66666,inf=0x3f3f3f3f;queue
         
          q;int n,num,yy,ans,jy,w[N],v[N],first[N],next[N],tot,vis[N];void add(int x,int y,int z){w[tot]=z,v[tot]=y,next[tot]=first[x],first[x]=tot++;}bool tell(){    memset(vis,-1,sizeof(vis)),vis[1]=0;    queue
          
           q;q.push(1); while(!q.empty()){ int t=q.front();q.pop(); for(int i=first[t];~i;i=next[i])if(w[i]&&!~vis[v[i]]) vis[v[i]]=vis[t]+1,q.push(v[i]); }return ~vis[n];}int zeng(int x,int y){ if(x==n)return y; int r=0; for(int i=first[x];~i;i=next[i])if(vis[v[i]]==vis[x]+1&&w[i]){ int t=zeng(v[i],min(y-r,w[i])); w[i]-=t,w[i^1]+=t,r+=t; } if(!r)vis[x]=-1; return r;}int main(){ memset(first,-1,sizeof(first)); scanf("%d",&n); for(int i=1;i