BZOJ-1433: [ZJOI2009]假期的宿舍（最大流）

题目：http://www.lydsy.com/JudgeOnline/problem.php?id=1433

赤赤裸裸的最大流水题，水过去就可以啦。

代码:

#include <cstdio>
#include <algorithm>
#include <cstring>
 
using namespace std ;
 
#define MAXN 10100
#define AddEdge( s , t , f ) Add( s , t , f ) , Add( t , s , 0 )
#define inf 0x7fffffff
 
struct edge {
    int t , f , next ;
} e[ MAXN ] ;
 
int head[ MAXN ] , en ;
 
void Add( int s , int t , int f ) {
    e[ en ].t = t , e[ en ].f = f , e[ en ].next = head[ s ] ;
    head[ s ] = en ++ ;
}
 
int node[ MAXN ][ 2 ] , V , S , T ;
int gap[ MAXN ] , h[ MAXN ] , d[ MAXN ] ;
 
int sap( int v , int flow ) {
    if ( v == T ) return flow ;
    int rec = 0 ;
    for ( int i = d[ v ] ; i != - 1 ; i = e[ i ].next ) {
        if ( e[ i ].f && h[ v ] == h[ e[ i ].t ] + 1 ) {
            int ret = sap( e[ i ].t , min( flow - rec , e[ i ].f ) ) ;
            e[ i ].f -= ret , e[ i ^ 1 ].f += ret , d[ v ] = i ;
            if ( ( rec += ret ) == flow ) return flow ;
        }
    }
    if ( ! ( -- gap[ h[ v ] ] ) ) h[ S ] = T ;
    gap[ ++ h[ v ] ] ++ , d[ v ] = head[ v ] ;
    return rec ;
}
 
int maxflow(  ) {
    memset( gap , 0 , sizeof( gap ) ) ; 
    memset( h , 0 , sizeof( h ) ) ;
    for ( int i = 0 ; i ++ < T ; ) d[ i ] = head[ i ] ;
    gap[ 0 ] = T ;
    int flow = 0 ;
    while ( h[ S ] < T ) flow += sap( S , inf ) ;
    return flow ;
}
 
int a[ MAXN ] , b[ MAXN ] , n , tot ;
 
int main(  ) {
    scanf( "%d" , &tot ) ;
    while ( tot -- ) {
        int cnt = 0 ;
        en = V = 0 ; 
        scanf( "%d" , &n ) ;
        for ( int i = 0 ; i ++ < n ; ) {
            node[ i ][ 0 ] = ++ V , node[ i ][ 1 ] = ++ V ;
        }
        S = ++ V ; T = ++ V ;
        for ( int i = 0 ; i ++ < V ; ) head[ i ] = - 1 ;
        for ( int i = 0 ; i ++ < n ; ) scanf( "%d" , a + i ) ;
        for ( int i = 0 ; i ++ < n ; ) scanf( "%d" , b + i ) ;
        for ( int i = 0 ; i ++ < n ; ) {
            if ( a[ i ] ) AddEdge( node[ i ][ 1 ] , T , 1 ) ;
            if ( ! ( a[ i ] && b[ i ] ) ) AddEdge( S , node[ i ][ 0 ] , 1 ) , ++ cnt ;
            AddEdge( node[ i ][ 0 ] , node[ i ][ 1 ] , 1 ) ;
        }
        for ( int i = 0 ; i ++ < n ; ) {
            for ( int j = 0 ; j ++ < n ; ) {
                int x ; scanf( "%d" , &x ) ;
                if ( x ) AddEdge( node[ i ][ 0 ] , node[ j ][ 1 ] , 1 ) ;
            }
        }
        printf( maxflow(  ) == cnt ? "^_^\n" : "T_T\n" )  ;
    }
    return 0 ;
}