/// <summary>
/// Kiem tra tap muc thuoc tid
/// </summary>
/// <param name="tid">Transaction id cua F</param>
/// <param name="muc">Mot muc cua L, Example: {1,2}</param>
/// <returns></returns>
public static bool ThuocTid(ItemSetsCollection tid, Itemsets muc)
{
Itemsets p = new Itemsets(muc);
p.RemoveAt(muc.Count - 1);
// p: c-c[k]
List <int> q = new List <int>(muc);
q.RemoveAt(muc.Count - 2);
//q: c-c[k-1]
int count = 0;
foreach (Itemsets item in tid)
{
if (item.IsEqual(p))
{
count += 1;
}
if (item.IsEqual(q))
{
count += 1;
}
}
return(count >= 2);
}
/// <summary>
/// Thuat toan apriori_gen, sinh ra tap ung vien C tu tap L(k-1)
/// </summary>
/// <param name="lPrevious">L(k-1)</param>
/// <returns></returns>
public static ItemSetsCollection AprioriGen(ItemSetsCollection lPrevious)
{
ItemSetsCollection result = new ItemSetsCollection();
if (lPrevious.Count <= 1)
{
return(result);
}
int k = lPrevious[0].Count;
for (int i = 0; i < lPrevious.Count - 1; i++)
{
Itemsets p = new Itemsets(lPrevious[i]);
p.RemoveAt(k - 1);
for (int j = i + 1; j < lPrevious.Count; j++)
{
Itemsets q = new Itemsets(lPrevious[j]);
q.RemoveAt(k - 1);
if (p.IsEqual(q))
{
q.Add(lPrevious[i][k - 1]);
q.Add(lPrevious[j][k - 1]);
result.Add(q);
}
}
}
return(result);
}
