brute force是什么意思？我去.. 暴力的意思... 还以为是禽兽之力呢.. 呵呵
#include<stdio.h>int ans[111111];int main()
{int a,b,n;scanf( "%d %d %d",&a,&b,&n );ans[0]=a;a%=b;bool found;for( int i=1;i<=n;i++ ){found=false;for( int j=0;j<10;j++ )if( (a*10+j)%b==0 ){found=true;ans[i]=j;a=(a*10+j)%b;break;}if( !found )break;}if( !found )printf( "-1" );elsefor( int i=0;i<=n;i++ )printf( "%d",ans[i] );printf( "\n" );return 0;
}