hdu 2034 //水题，求差…

#include"iostream"
#include"algorithm"
using namespace std;
int a[101];
int b[101];
int main()
{
    intn,m,i,j;
    boolmark;
   while(scanf("%d%d",&n,&m)!=EOF && !(m==0 &&n==0))
    {
    for(i=0;i
        scanf("%d",&a[i]);
    for(i=0;i
        scanf("%d",&b[i]);
    sort(a,a+n);
    sort(b,b+m);
    
    i=0;
    j=0;
    mark=true;
    while(i
    {
              while(j
                  j++;
              if(j==m)
                  break;
              if(b[j]==a[i])
                  {
                            i++;
                            j++;
                            
                  }
              else
              {
                  printf("%d ",a[i]);
                  mark=false;
                  i++;
                  
                  
              }
    }
    if(i
        mark=false;
    for(;i
              printf("%d ",a[i]);
    if(mark)
        printf("NULL");
        
    printf("\n");
    }
   
   
    return0;
}