public static List <string[]> LeftJoin(HashTable hashTableA, HashTable hashTableB)
{
List <string[]> results = new List <string[]>();
foreach (var bucket in hashTableA.Contents)
{
if (bucket != null)
{
foreach (var kvPair in bucket)
{
string[] result = new string[] { kvPair.Key, kvPair.Value, null };
results.Add(result);
if (hashTableB.Contains(kvPair.Key))
{
result[2] = hashTableB.Get(kvPair.Key);
}
}
}
}
return(results);
}
static void Main(string[] args)
{
Console.WriteLine("Hello World!");
HashTable synonyms = new HashTable(5);
synonyms.Add("fond", "enamored");
synonyms.Add("wrath", "anger");
synonyms.Add("diligent", "employed");
HashTable antonyms = new HashTable(5);
antonyms.Add("fond", "averse");
antonyms.Add("wrath", "delight");
antonyms.Add("guide", "follow");
string[][] joined = LeftJoin(synonyms, antonyms);
for (int i = 0; i < joined.Length; i++)
{
Console.WriteLine(joined[i][0] + joined[i][1] + joined[i][2]);
}
}
/// <summary>
/// Call LeftJoinHashTable method of the HashTable class to try out solution
/// </summary>
public static void TryLeftJoin()
{
//instantiate new Hashtable ht1 and add contents
HashTable ht1 = new HashTable();
ht1.Add("fond", "enamored");
ht1.Add("wrath", "anger");
ht1.Add("diligent", "employed");
ht1.Add("outfit", "garb");
ht1.Add("guide", "usher");
//instantiate new Hashtable ht2 and add contents
HashTable ht2 = new HashTable();
ht2.Add("fond", "averse");
ht2.Add("wrath", "delight");
ht2.Add("diligent", "idle");
ht2.Add("guide", "follow");
ht2.Add("flow", "jam");
//pass the 2 hashtables to the method to left join them
HashTable ht3 = ht1.LeftJoinHashTable(ht1, ht2);
//log to the view to prove it was returned
for (int i = 0; i < ht3.HashArray.Length; i++)
{
if (ht3.HashArray[i] != null)
{
Console.WriteLine($"{ht3.HashArray[i].Key} : {ht3.HashArray[i].Value}");
if (ht3.HashArray[i].Next != null)
{ //checks if there is another node at that key
//if there is another node, output that
//this means that there was another value for that key on the 2nd table
Console.WriteLine($"{ht3.HashArray[i].Next.Value}");
}
}
}
}
/// <summary>
/// Left joins two HashTable<string> objects.
/// </summary>
/// <param name="leftTable">
/// HashTable<string>: the HashTable<string> to be used as the left table in the left join
/// </param>
/// <param name="rightTable">
/// HashTable<string>: the HashTable<string> to be used as the right table in the left join
/// </param>
/// <returns>
/// HashTable<string>: a HashTable<LeftJoinNode>, containing the keys and values from leftTable and rightTable, left joined together
/// </returns>
public static HashTable <LeftJoinNode> LeftJoinHashTables(HashTable <string> leftTable, HashTable <string> rightTable)
{
HashTable <LeftJoinNode> leftJoin = new HashTable <LeftJoinNode>();
for (int i = 0; i < leftTable.HashMap.Length; i++)
{
if (leftTable.HashMap[i] != null)
{
var currNode = leftTable.HashMap[i].First;
while (currNode != null)
{
LeftJoinNode newLeftJoinNode = new LeftJoinNode(currNode.Value.Value);
if (rightTable.Contains(currNode.Value.Key))
{
newLeftJoinNode.RightValue = rightTable.Get(currNode.Value.Key);
}
leftJoin.Add(currNode.Value.Key, newLeftJoinNode);
currNode = currNode.Next;
}
}
}
return(leftJoin);
}
