diff --git a/thu_dsa/chp2/Vector.h b/thu_dsa/chp2/Vector.h
index 9829fab..2ef7ba0 100644
--- a/thu_dsa/chp2/Vector.h
+++ b/thu_dsa/chp2/Vector.h
@@ -54,6 +54,9 @@ public:
 	T pop(int index);
 	T pop(int lo, int hi);//return the last element popped
 	int remove(T const &elem);//remove first element matched, return index, -1 if not found
+	int unique(void); //return the number of elements deleted
+	void map(void(*visit)(T&));
+	template <typename VST> void map(VST& visit);
 };
 
 //protected methods
@@ -165,4 +168,27 @@ int Vector<T>::remove(T const &elem){
 	return pos;
 }
 
+template <typename T>
+int Vector<T>::unique(){
+	int count = 0;
+	for(int pos = 1; pos != _size;){
+		if (find(_elem[pos], 0, pos) == -1) ++pos;
+		else{
+			pop(pos);
+			++count;
+		}
+	}
+	return count;
+}
+
+template <typename T>
+void Vector<T>::map(void(*visit)(T&)){
+	for (int ix = 0; ix != _size; ++ix) visit(_elem[ix]);
+}
+
+template <typename T> template <typename VST>
+void Vector<T>::map(VST& visit) {
+	for (int ix = 0; ix != _size; ++ix) visit(_elem[ix]);
+}
+
 #endif
diff --git a/thu_dsa/chp2/testVector.cpp b/thu_dsa/chp2/testVector.cpp
index 0ccc6ed..a98d5fb 100644
--- a/thu_dsa/chp2/testVector.cpp
+++ b/thu_dsa/chp2/testVector.cpp
@@ -10,6 +10,8 @@ void test_access();
 void test_insert();
 void test_delete();
 void test_find();
+void test_unique();
+void test_map();
 
 int main(){
 	test_constructor();
@@ -17,6 +19,8 @@ int main(){
 	test_insert();
 	test_delete();
 	test_find();
+	test_unique();
+	test_map();
 
 	system("pause");
 	return 0;
@@ -120,3 +124,32 @@ void test_find(){
 
 	cout << "test passed." << endl;
 }
+
+void test_unique(){
+	cout << "run test_unique...";
+	int A[] = { 2,3,4,6,1,0,9,8,7,5,9,2,3,5,6,3,3,5 };
+	Vector<int> v(A, 0, 10);
+	assert(v.unique() == 0);
+	assert(v.getSize() == 10);
+	
+	v = Vector<int>(A, 18);
+	assert(v.unique() == 8);
+	assert(v.getSize() == 10);
+	assert(v[9] == 5);
+
+	cout << "test passed." << endl;
+}
+
+template <typename T>
+void Increase(T & elem) { ++elem; }
+void test_map(){
+	cout << "run test_map...";
+	float A[] = { 2,3,4,6,1,0,9,8,7,5,9,2,3,5,6,3,3,5 };
+	Vector<float> v(A, 10);
+
+	v.map(Increase);
+	for (int ix = 0; ix != v.getSize(); ++ix)
+		assert(v[ix] == A[ix] + 1);
+
+	cout << "test passed." << endl;
+}