BZOJ大视野 1059: [ZJOI2007]矩阵游戏 解题报告

二分图匹配，用行匹配列。

code:

/**************************************************************
    Problem: 1059
    Language: C++
    Result: Accepted
    Time:316 ms
    Memory:1744 kb
****************************************************************/

// Forever_LF
#include
#include
#include
using namespace std;

struct node
{
    int x,y,next;
}a[40001]; int len,first[201];
int L[201];
bool ev[201];

void ins( int x, int y )
{
    len++;
    a[len].x=x; a[len].y=y;
    a[len].next = first[x]; first[x] = len;
}
bool ex( int x )
{
    for ( int k=first[x];k;k=a[k].next )
    {
        int y=a[k].y;
        if ( ev[y] ) continue ;
        ev[y] = true ;
        if ( !L[y] || ex( L[y] ) )
        {
            L[y] = x;
            return true ;
        }
    }
    return false ;
}

int main()
{
    int n,m,t,i,j,l;
    bool v;
    scanf ( "%d" ,&m);
    while ( m-- )
    {
        memset ( first,0, sizeof first );
        memset ( L,0, sizeof L );
        len = 0; v = true ;

        scanf ( "%d" ,&n);
        for ( i=1;i<=n;i++ )
            for ( j=1;j<=n;j++ )
            {
                scanf ( "%d" ,&l);
                if ( l ) ins( i,j );
            }
        for ( i=1;i<=n;i++ )
        {
            memset ( ev, false , sizeof ev );
            if ( !ex( i ) )
            {
                v = false ;
                break ;
            }
        }
        if ( v ) printf ( "Yes\n" );
        else printf ( "No\n" );
    }
    return 0;
}