diff --git a/thu_dsa/chp10/LeftistHeap.h b/thu_dsa/chp10/LeftistHeap.h
new file mode 100644
index 0000000..8b06e1f
--- /dev/null
+++ b/thu_dsa/chp10/LeftistHeap.h
@@ -0,0 +1,72 @@
+#ifndef LEFTISTHEAP_H_
+#define LEFTISTHEAP_H_
+
+#include "PriorityQueue.h"
+#include "../chp5/binTree.h"
+
+#define NPL(X) (X == nullptr? 0: X->npl)
+
+template <typename K, typename V>
+class LeftHeap: public PriorityQueue<K, V>, public BinTree<entry<K, V>>{
+public:
+	//constructor
+	LeftHeap() = default;
+	LeftHeap(entry<K, V>* src, int n) { for (int ix = 0; ix != n; ++ix) insert(src[ix]); }		//brute force algorithm
+
+	//public interfaces
+	int size() { return BinTree<entry<K, V>>::size(); }
+	bool empty() { return size() == 0; }
+	entry<K, V> getMax() { return __root->data; }
+	entry<K, V> delMax();
+	void        insert(entry<K, V> e);
+	void        insert(K key, V value) { insert(entry<K, V>(key, value)); }
+};
+
+#define T entry<K, V>
+
+template<typename K, typename V>
+BinNodePosi(T) merge(BinNodePosi(T) a, BinNodePosi(T) b){
+	if (a == nullptr) return b;
+	if (b == nullptr) return a;
+	BinNodePosi(T) temp;
+	if (a->data < b->data){//swap a and b
+		temp = a;
+		a = b;
+		b = temp;
+	}
+	if (a->rightChild == nullptr) a->rightChild = b;
+	else a->rightChild = merge(a->rightChild, b);
+	a->rightChild->parent = a;
+
+	if (NPL(a->leftChild) < NPL(a->rightChild)) {// swap the right chlid and left child of a
+		temp = a->leftChild;
+		a->leftChild = a->rightChild;
+		a->rightChild = temp;
+	}
+	a->npl = NPL(a->rightChild) + 1;
+	return a;
+}
+
+//public interfaces
+
+template <typename K, typename V>
+void LeftHeap<K, V>::insert(entry<K, V> e){
+	BinNodePosi(T) newNode = new BinNode<T>(e);
+	newNode->npl = 1;
+	__root = merge(__root, newNode);
+	__root->parent = nullptr;
+	++__size;
+}
+
+template <typename K, typename V>
+entry<K, V> LeftHeap<K, V>::delMax(){
+	entry<K, V> res = getMax();
+	__root = merge(__root->leftChild, __root->rightChild);
+	if (__root) __root->parent = nullptr;
+	--__size;
+	return res;
+}
+
+#undef  T
+
+#endif
diff --git a/thu_dsa/chp10/testHeap.cpp b/thu_dsa/chp10/testHeap.cpp
index 174071e..8d3ea59 100644
--- a/thu_dsa/chp10/testHeap.cpp
+++ b/thu_dsa/chp10/testHeap.cpp
@@ -1,4 +1,5 @@
 #include "CompleteBinaryHeap.h"
+#include "LeftistHeap.h"
 #include <iostream>
 #include <cassert>
 using std::cout;
diff --git a/thu_dsa/chp10/testLeftHeap.cpp b/thu_dsa/chp10/testLeftHeap.cpp
new file mode 100644
index 0000000..d6842c3
--- /dev/null
+++ b/thu_dsa/chp10/testLeftHeap.cpp
@@ -0,0 +1,59 @@
+#include "LeftistHeap.h"
+#include "../chp4/Queue.h"
+#include <iostream>
+#include <cassert>
+using std::cout;
+using std::endl;
+
+void test_insert();
+void test_max();
+
+int main(){
+	cout << "Running tests" << endl;
+
+	test_insert();
+	test_max();
+
+	cout << "All tests passed." << endl;
+	system("pause");
+	return 0;
+}
+
+#define T  entry<int, int>
+void test_insert(){
+	int keys[] = { 5, 4, 7, 9, 1, 2, 8, 3, 6, 0 };
+	int levelOrder[] = { 9, 8, 7, 2, 3, 5, 6, 1, 4, 0 };
+	LeftHeap<int, int> heap;
+	for (int ix = 0; ix != 10; ++ix) {
+		assert(heap.size() == ix);
+		heap.insert(entry<int, int>(keys[ix], 0));
+	}
+	//level-order traversal
+	int ix = 0;
+	Queue<BinNodePosi(T)> q;
+	BinNodePosi(T) curr;
+	q.enqueue(heap.root());
+	while(!q.empty()){
+		curr = q.dequeue();
+		assert(curr->data.key == levelOrder[ix++]);
+		if (curr->leftChild) q.enqueue(curr->leftChild);
+		if (curr->rightChild) q.enqueue(curr->rightChild);
+	}
+
+	cout << "test_insert passed." << endl;
+}
+
+void test_max(){
+	int keys[] = { 5, 4, 7, 9, 1, 2, 8, 3, 6, 0 };
+	LeftHeap<int, int> heap;
+	for (int ix = 0; ix != 10; ++ix) {
+		assert(heap.size() == ix);
+		heap.insert(entry<int, int>(keys[ix], 0));
+	}
+	for(int ix = 0; ix != 10; ++ix){
+		assert(heap.getMax().key == 9 - ix);
+		assert(heap.delMax().key == 9 - ix);
+		assert(heap.size() == 9 - ix);
+	}
+	cout << "test_max passed." << endl;
+}