POJ 1087 A Plug for UNIX

POJ 1087 A Plug for UNIX
这是本人AC的第一道网络流建模的题目哇~内牛满面!!!做了两天才AC……
网络流题目重在 构图
以下是我的代码:
#include < iostream >
#include
< string >
#include
< queue >
#include
< map >
#include
< algorithm >
#include
< cstdio >
#include
< cstring >
using   namespace  std;
const   int  kMaxn( 507 );
const   int  kInf( 77777 );

int  a,b,c;
map
< string , int >  r;
int  n,source,sink,maxflow,cap[kMaxn][kMaxn],flow[kMaxn][kMaxn];

void  SAP()
{
    
int  d[kMaxn],num[kMaxn],p[kMaxn];

    memset(flow,
0 ,kMaxn * kMaxn * sizeof ( int ));
    memset(d,
0x7f ,kMaxn * sizeof ( int ));
    memset(num,
0 ,kMaxn * sizeof ( int ));
    queue
< int >  q;
    d[sink]
= 0 ;
    num[
0 ] ++ ;
    q.push(sink);
    
while ( ! q.empty())
    {
        
int  v(q.front());q.pop();
        
for ( int  u = 1 ;u <= n;u ++ )
            
if (d[u] >= &&  cap[u][v] > flow[u][v])
            {
                d[u]
= d[v] + 1 ;
                num[d[u]]
++ ;
                q.push(u);
            }
    }

    maxflow
= 0 ;
    
int  u(source),v;
    
while (d[source] < n)
    {
        v
=- 1 ;
        
for ( int  i = 1 ;i <= n;i ++ )
            
if (cap[u][i] > flow[u][i]  &&  d[u] == d[i] + 1 )
            {v
= i; break ;}
        
if (v !=- 1 )
        {
            p[v]
= u;u = v;
            
if (u == sink)
            {
                
int  add(kInf);
                
for (u = sink;u != source;u = p[u])
                    add
= min(add,cap[p[u]][u] - flow[p[u]][u]);
                maxflow
+= add;
                
for (u = sink;u != source;u = p[u])
                {
                    flow[p[u]][u]
+= add;
                    flow[u][p[u]]
-= add;
                }
            }
        }
        
else
        {
            num[d[u]]
-- ;
            
if ( ! num[d[u]])
                
return ;
            d[u]
= n;
            
for (v = 1 ;v <= n;v ++ )
                
if (cap[u][v] > flow[u][v])
                    d[u]
= min(d[u],d[v] + 1 );
            num[d[u]]
++ ;
            
if (u != source)
                u
= p[u];
        }
    }
}

int  main()
{
    source
= 1 ;
    sink
= 2 ;
    n
= 2 ;
    memset(cap,
0 ,kMaxn * kMaxn * sizeof ( int ));

    cin
>> a;
    
for ( int  i = 1 ;i <= a;i ++ )
    {
        
string  t;
        cin
>> t;
        r[t]
= ( ++ n);
        cap[n][sink]
++ ;
    }
    cin
>> b;
    
for ( int  i = 1 ;i <= b;i ++ )
    {
        
string  t1,t2;
        cin
>> t1 >> t2;
        r[t1]
= ( ++ n);
        cap[source][n]
++ ;
        
if ( ! r.count(t2))
            r[t2]
= ( ++ n);
        cap[r[t1]][r[t2]]
++ ;
    }
    cin
>> c;
    
for ( int  i = 1 ;i <= c;i ++ )
    {
        
string  t1,t2;
        cin
>> t1 >> t2;
        
if ( ! r.count(t1))
            r[t1]
= ( ++ n);
        
if ( ! r.count(t2))
            r[t2]
= ( ++ n);
        cap[r[t1]][r[t2]]
= kInf;
    }

    SAP();

    printf(
" %d\n " ,b - maxflow);

    
return   0 ;
}

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