HDU 2141 Can you find it?

#include <iostream>
#include <algorithm>
using namespace std;
int a[505],b[505],c[505];
int s[250005];
bool find(int x,int l,int r)
{
if(l>r)
return false;
int mid=(l+r)/2;
if(s[mid]==x)
return true;
else if(s[mid]>x)
return find(x,l,mid-1);
else return find(x,mid+1,r);
}
int main()
{
int L,n,m;
int i,j,k;
int t,sum,cnt = 1;
while(cin>>L>>n>>m)
{
for(i=0;i<L;i++)cin>>a[i];
for(i=0;i<n;i++)cin>>b[i];
for(i=0;i<m;i++)cin>>c[i];
for(k=0,i=0;i<L;i++)
for(j=0;j<n;j++)
s[k++]=a[i]+b[j];
sort(s,s+k);
cin>>t;
cout<<"Case "<<cnt++<<":\n";
while(t--){
cin>>sum;
for(j=0;j<m;j++)
if (find(sum-c[j],0,k-1))
break;
if(j==m)cout<<"NO\n";
else cout<<"YES\n";
}
}
return 0;
}