diff --git a/YASI_12/YASI_12.vcxproj b/YASI_12/YASI_12.vcxproj
index c1e149a..89e2516 100644
--- a/YASI_12/YASI_12.vcxproj
+++ b/YASI_12/YASI_12.vcxproj
@@ -85,6 +85,7 @@
     <ClInclude Include="ds.dictionary.h" />
     <ClInclude Include="ds.doublylinkedlist.h" />
     <ClInclude Include="ds.hashtablebase.h" />
+    <ClInclude Include="ds.HopScotchHashTable.h" />
     <ClInclude Include="ds.IntLinearProbingHashTable.h" />
     <ClInclude Include="ds.iterator.h">
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">false</ExcludedFromBuild>
diff --git a/YASI_12/YASI_12.vcxproj.filters b/YASI_12/YASI_12.vcxproj.filters
index 812c1d4..cf648d9 100644
--- a/YASI_12/YASI_12.vcxproj.filters
+++ b/YASI_12/YASI_12.vcxproj.filters
@@ -123,6 +123,9 @@
       <Filter>Header Files\Dictionary</Filter>
     </ClInclude>
     <ClInclude Include="ds.IntLinearProbingHashTable.h">
+      <Filter>Header Files\Dictionary</Filter>
+    </ClInclude>
+    <ClInclude Include="ds.HopScotchHashTable.h">
       <Filter>Header Files</Filter>
     </ClInclude>
   </ItemGroup>
diff --git a/YASI_12/ds.HopScotchHashTable.h b/YASI_12/ds.HopScotchHashTable.h
new file mode 100644
index 0000000..7cecc7e
--- /dev/null
+++ b/YASI_12/ds.HopScotchHashTable.h
@@ -0,0 +1,103 @@
+#pragma once
+#include "common.h"
+#include "ds.IntLinearProbingHashTable.h"
+
+namespace yasi{
+namespace ds{
+using namespace std;
+
+template<class Value> 
+struct HopScotchEntry{
+	size_t	key;
+	Value	value;
+	int		bitField; // map of bucket elements
+	HopScotchEntry(const size_t& k) : key(k){}
+	HopScotchEntry(const size_t& k, const value& v) : key(k), value(v){}
+	HopScotchEntry(const size_t& k, const value& v, const int& bf) : 
+		key(k), value(v),bitField(bf){}
+
+};
+
+// a hash table with integer key
+template<
+	class Value = size_t,
+	class HashFunction = IntHashFunction<int> >
+class HopScotchHashTable
+	: public IntLinearProbingHashTable <
+	Value, HashFunction, HopScotchEntry<Value> > {
+
+	///////////////// enable testing ///////////////
+	friend class HopScotchHashTableTest;
+	template<typename A, typename B, typename C>
+	friend class LinearProbingHashTableTestBase;
+
+public:
+	typedef size_t Key;
+	typedef KVPair<Key, Value> EntryType; // must have a public member `key'
+	typedef EntryType	BucketType; // each bucket holds an EntryType object
+	typedef EntryType	Pair; // which is actually a key-value pair
+	typedef EntryType* BucketEntryPtr; // ptr to an entry object
+	typedef Key		KeyType;
+	typedef Value	ValueType;
+
+protected:
+	typedef IntLinearProbingHashTable < Value, HashFunction >
+		base;
+
+	virtual void copyTable(BucketType* oldTable, const unsigned int oldSize) override{
+		h::copyTable(oldTable, oldSize);
+	}
+
+	
+	//---------- HopScotch Properties/Methods ----------
+	static unsigned int INIT_H = 32;
+	unsigned size_t H; // the neighborhood size
+	// push this entry to the right
+	bool pushToRight(const int bucket){}
+	// fill this bucket with an entry from the left
+	void pullFromLeft(const int bucket){}
+
+public:
+
+	virtual ~HopScotchHashTable(){}
+	HopScotchHashTable(unsigned int logSize = INIT_LOGSIZE, unsigned int H = INIT_H) :H(H),IntLinearProbingHashTable(logSize){}
+
+};
+
+////////// test IntLinearProbingHashTable
+// inherit tests from base class, just redefine the types
+
+class HopScotchHashTableTest 
+//	: public LinearProbingHashTableTestBase<
+//	HopScotchHashTable<int, Mod8Function<int> >,
+//	HopScotchHashTable<int, Mod16Function<int> >,
+//	HopScotchHashTable<int, Mod32Function<int> >
+//>
+{
+	//
+protected:
+	typedef HopScotchHashTable<int, Mod8Function<int> > IntHashTable8;
+	typedef HopScotchHashTable<int, Mod16Function<int> > IntHashTable16;
+	typedef IntHashTable16 IntHashTable; // default
+	typedef IntLinearProbingHashTable<int, Mod32Function<int> > IntHashTable32;
+	typedef IntHashTable::BucketType BucketType;
+	typedef IntHashTable::BucketEntryPtr BucketEntryPtr;
+	typedef IntHashTable::Pair Pair;
+
+public:
+	// inherit all public tests
+	void pushToRight(){
+		IntHashTable h(4, 4); // size 16, H=4
+		h.table[2] = HopScotchEntry<int>( 2, 2, 0 );
+	}
+
+};
+//ADD_TEST_F(HopScotchHashTableTest, insert);
+//ADD_TEST_F(HopScotchHashTableTest, copyTable);
+//ADD_TEST_F(HopScotchHashTableTest, growCondition);
+//ADD_TEST_F(HopScotchHashTableTest, shrinkCondition);
+//ADD_TEST_F(HopScotchHashTableTest, isKeyZero);
+//ADD_TEST_F(HopScotchHashTableTest, remove);
+
+}
+}
\ No newline at end of file
diff --git a/YASI_12/ds.IntLinearProbingHashTable.h b/YASI_12/ds.IntLinearProbingHashTable.h
index ca713cf..84fb1bd 100644
--- a/YASI_12/ds.IntLinearProbingHashTable.h
+++ b/YASI_12/ds.IntLinearProbingHashTable.h
@@ -9,10 +9,11 @@ namespace yasi{
 		// a hash table with integer key
 		template<
 			class Value = size_t,
-			class HashFunction = IntHashFunction<int> >
+			class HashFunction = IntHashFunction<int> ,
+			class EntryType = KVPair<size_t, Value> >
 		class IntLinearProbingHashTable
 			: public LinearProbingHashTable <
-			size_t, Value, HashFunction, KVPair<size_t, Value> > {
+			size_t, Value, HashFunction, EntryType > {
 
 			///////////////// enable testing ///////////////
 			friend class IntLinearProbingHashTableTest;