POJ 1966 求无向图点连通度

思路：

n^2枚举（必须要n^2枚举啊）+拆点

特此嘲讽网上诸多垃圾题解，你们许多都是错的 —yyh

//By SiriusRen
#include <queue>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
#define N 5555
int n,m,xx,yy,inf=0x3fffff,ans,ed=105;
struct Node{int x,y;}point[N];
struct Dinic{
    int first[107],next[N],v[N],w[N],tot,vis[107];
    void solve(int x,int y){
        memset(first,-1,sizeof(first)),tot=0;
        add(0,x,inf),add(x,x+n,inf),add(y,y+n,inf),add(y+n,105,inf);
        for(int i=1;i<=n;i++)add(i,i+n,1);
        for(int i=1;i<=m;i++)add(point[i].x+n,point[i].y,inf),add(point[i].y+n,point[i].x,inf);
        ans=min(ans,x=flow());
    }
    void add(int x,int y,int z){Add(x,y,z),Add(y,x,0);}
    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[0]=0;
        queue<int>q;q.push(0);
        while(!q.empty()){
            int t=q.front();q.pop();
            for(int i=first[t];~i;i=next[i])
                if(vis[v[i]]==-1&&w[i])
                    vis[v[i]]=vis[t]+1,q.push(v[i]);
        }
        return vis[ed]!=-1;
    }
    int zeng(int x,int y){
        if(x==ed)return y;
        int r=0;
        for(int i=first[x];~i&&y>r;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 flow(){
        int jy=0,tmp;
        while(tell())while(tmp=zeng(0,inf))jy+=tmp;
        return jy;
    }
}dinic;
int main(){
    while(~scanf("%d%d",&n,&m)){
        ans=inf;
        for(int i=1;i<=m;i++){
            scanf(" (%d,%d)",&point[i].x,&point[i].y);
            point[i].x++,point[i].y++;
        }
        for(int i=1;i<=n;i++)
            for(int j=1;j<=n;j++)
                if(i!=j)dinic.solve(i,j);
        if(ans==inf)printf("%d\n",n);
        else printf("%d\n",ans);
    }
}