POJ 2289-Jamie's Contact Groups binary + Multi-matching of bipartite graphs

Question:

To group the address book... each person can only be assigned to one of its specific groups. Ask how many groups can be minimized ..

Question:

At the beginning, I got a wrong question. I thought it was necessary to minimize the group difference between the largest group and the smallest group. Then I fell down...

By the question, it is still very simple... the capacity of the binary enumeration... and then the multi-matching judgment of the Binary Graph...

Program:

#include<iostream>#include<stdio.h>#include<algorithm>#include<cmath>#include<stack>#include<string.h>#include<queue>#define ll long long#define esp 1e-5#define MAXN 1006#define MAXM 5000000#define oo 100000007using namespace std;int n,m,num[MAXN],line[MAXN][MAXN];bool g[MAXN][MAXN],used[MAXN];bool dfs(int x,int C){       for (int i=1;i<=m;i++)          if (g[x][i] && !used[i])          {                  used[i]=true;                  if (num[i]<C)                  {                        line[i][++num[i]]=x;                        return true;                  }                  for (int j=1;j<=num[i];j++)                     if (dfs(line[i][j],C))                     {                             line[i][j]=x;                             return true;                     }          }       return false;}bool getmax(int C){       memset(num,0,sizeof(num));       for (int i=1;i<=n;i++)       {              memset(used,false,sizeof(used));              if (!dfs(i,C)) return false;       }              return true;}int main()  {                  int i,x;       char c;        while (~scanf("%d%d",&n,&m) && n)       {                  memset(g,false,sizeof(g));               for (i=1;i<=n;i++)                {                      do { c=getchar(); }while (c<'0' || c>'9');                      while (1)                      {                             x=0;                             while (c>='0' && c<='9')                             {                                    x=x*10+c-'0';                                    c=getchar();                             }                             g[i][x+1]=true;                             if (c=='\n') break;                               do { c=getchar(); }while (c==' ');                             if (c=='\n') break;                                               }                                     }               int l=0,r=1005,mid;                while (r-l>1)               {                       mid=r+l>>1;                       if (!getmax(mid)) l=mid;                                    else r=mid;               }               printf("%d\n",r);       }       return 0;  }