hdu-----(1179)Ollivanders: Makers of Fine Wands since 382 BC.(二分匹配)

Ollivanders: Makers of Fine Wands since 382 BC.

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/65536 K (Java/Others)
Total Submission(s): 935    Accepted Submission(s): 523

Problem Description

In
Diagon Alley ,there is only one Wand-seller,peeling gold letters over
the door read Ollivanders: Makers of Fine Wands since 382 BC.A single
wand lay on a faded purple cushion in the dusty window.
A tinkling
bell rang somewhere in the depths of the shop as they stepped inside.It
was a tiny place,empty execpt for a single spindly chair which Hagrid
sat on to wait.Harry felt strangely as though he had entered a very
strict library;he swallowd a log of new questions which had just
occurred to him and looked instead at the thousands of narrow boxes
piled neatly right up to the ceiling.For some reason,the back of his
neck prickled.The very dust and silence in here seemed to tingle with
some secret magic.
'Good afternoon,'said a soft voice.Harry
jumped.Hagrid must have jumped,too,because there was a loud crunching
noise and he got quickly off the spindly chair.
An old man was standing before them, his wide pale eyes shining like moons through the gloom of the shop.
'Hello,' said Harry awkwardly.
'Ah
yes,' said the man. 'Yes,yes. I thought I'd be seeing you soon,Harry
Potter.'It wasn't a question.You have your mother's eyes. It seems only
yesterday she was in here herself,buying her first wand. Ten and a
quarter inches long, swishy, made of willow. Nice wand for charm work.'
Mor Ollivander moved closer to Harry.Harry wished he would blink.Those sivery eyes were a bit creepy.
'Your
father, on the other hand, favoured a mahogany wand.Eleven
inches.Pliable.A little more power and excellent for
transfiguration.Well ,I say your father favoured it - it's really the
wand that choosed the wizard, of cource.'

Yes, some wands fit
some wizards ,as we all know.But what Harry doesn't know is Ollivander
have met a big trouble.That's more than twenty years ago,When Harry's
father James Potter was still a student in Hogwarts.He went Diagon Alley
to buy new books,passing by Ollivander's shop.Ollivander was crazy for a
problem:He was too busy to choose most suitable wand for every
wizard.Even more,there are too many customer that day.Though Ollivader
knew every wand's favourite,he could not choose as many wizards as
possible to get the wands. So James Potter,a very clever man ,gave him a
magic disk with your program ,to help him sell wands as many as
possible.

Please notice: one wand can only be sold to one wizard, and one wizard can only buy one wand,too.

 

Input

There
are several cases. For each case, there is two integers N and M in the
first line,which mean there is N wizards and M wands(0 < N <= M
<= 100).
Then M lines contain the choices of each wand.The first
integer in i+1th line is Ki,and after these there are Ki integers Bi,j
which are the wizards who fit that wand.
(0<=Ki<=N,1<=Bi,j<=N)

 

Output

Only one integer,shows how many wands Ollivander can sell.

 

Sample Input

3 4
3 1 2 3
1 1
1 1
0

 

Sample Output

2

Hint

Hint

Wand 1 fits everyone, Wand 2,3 only fit the first wizard,and Wand 4 does not fit anyone.So Ollivanders can sell two wands:
sell Wand 1 to Wizard 2 and Wand 2 to Wizard 1,or sell Wand 1 to Wizard 3 and Wand 3 to Wizard 1 ,or some other cases. But
he cannot sell 3 wands because no 3 wands just fit 3 wizards.

 

Source

Gardon-DYGG Contest 1

代码：

 #include<cstring>
 #include<cstdio>
 #include<cstdlib>
 using namespace std;
 int const maxn=;
 int n,m;
 bool mat[maxn][maxn];
 bool vis[maxn];
 int mac[maxn];
 bool match(int x)
 {
     for(int i=;i<=n;i++)
     {
         if(mat[x][i]&&!vis[i]){
             vis[i]=;
             if(!mac[i]||match(mac[i])){
                 mac[i]=x;
                 return ;
             }
         }
     }
     return ;
 }
 int main(){
     int a,b;
     //freopen("test.in","r",stdin);
     while(scanf("%d%d",&n,&m)!=EOF){
        memset(mat,,sizeof(mat));
        memset(mac,,sizeof(mac));
        for(int i=;i<=m;i++){
          scanf("%d",&a);
         while(a--){
          scanf("%d",&b);
          mat[i][b]=;
         }
     }

     int ans=;
     for(int i=;i<=m;i++){
       memset(vis,,sizeof(vis));
       if(match(i))ans++;
     }
     printf("%d\n",ans);
  }
   return ;
 }