#include<cstdio>
#include<cstring>

bool rela[26][26];
char str[28] , ans , color[26];

char fun( char size )
{
    int i , j , k;
    memset( rela , 0 , sizeof( rela ) );
    memset( color , 1 , sizeof( color ) );
    ans = 1;
    for( i = 0 ; i < size ; i++ )
    {
        scanf("%s" , str );
        for( j = 2 ; str[ j ] >= 'A' ; j++ )
            rela[ i ][ str[ j ] - 'A' ] = 1;
    }
    for( k = 1 ; k < 4 ; k++ )
        for( i = 0 ; i < size ; i++ )
            if( color[ i ] == k )
                for( j = i+1 ; j < size ; j++ )
                    if( rela[ i ][ j ] && color[ j ] == k )
                        color[ j ] = k+1;
    for( i = 1 , ans = color[0] ; i < size ; i++ )
        if( color[ i ] > ans )
            ans = color[ i ];
    printf("%d channel%sneeded.\n" , ans , ans == 1 ? " " : "s " );
}

int main()
{
    char size;
    while( scanf("%d" , &size ) , size )
        fun( size );
    return 0;
}

• Re:四色定理+邻接矩阵+枚举 献丑了 (58) craig04 2013-11-21 11:32:04
  • Re:频道覆盖为啥一定是平面图了。。。凭啥就四色定理啊。。。 (116) chliul 2014-01-11 03:06:45
• Re:四色定理+邻接矩阵+枚举 献丑了 (1045) ry951111 2014-11-07 10:47:05
• Re:四色定理+邻接矩阵+枚举 献丑了 (80) ry951111 2014-11-07 10:48:45