diff --git a/README.md b/README.md
index 3f76540..72a07d5 100644
--- a/README.md
+++ b/README.md
@@ -582,6 +582,17 @@ TinySTL
 	*cp2 = ("C++");//write
 	assert(*cp1 == *cp3 && *cp3 == "zouxiaohang");
 	assert(*cp2 == "C++");
+
+
+
+
+####(19):union-find set
+
+    uf_set<10> uf;
+	uf.Union(0, 1);
+	uf.Union(2, 3);
+	uf.Union(3, 1);
+	assert(uf.Find(0) == uf.Find(2));
     
  
     
diff --git a/TinySTL/Test/UFSetTest.cpp b/TinySTL/Test/UFSetTest.cpp
new file mode 100644
index 0000000..ea87fda
--- /dev/null
+++ b/TinySTL/Test/UFSetTest.cpp
@@ -0,0 +1,17 @@
+#include "UFSetTest.h"
+
+namespace TinySTL{
+	namespace UFSetTest{
+		void testCase1(){
+			uf_set<10> uf;
+			uf.Union(0, 1);
+			uf.Union(2, 3);
+			uf.Union(3, 1);
+			assert(uf.Find(0) == uf.Find(2));
+		}
+
+		void testAllCases(){
+			testCase1();
+		}
+	}
+}
\ No newline at end of file
diff --git a/TinySTL/Test/UFSetTest.h b/TinySTL/Test/UFSetTest.h
new file mode 100644
index 0000000..ed952b7
--- /dev/null
+++ b/TinySTL/Test/UFSetTest.h
@@ -0,0 +1,15 @@
+#ifndef _UF_SET_TEST_H_
+#define _UF_SET_TEST_H_
+
+#include "../UFSet.h"
+#include <cassert>
+
+namespace TinySTL{
+	namespace UFSetTest{
+		void testCase1();
+
+		void testAllCases();
+	}
+}
+
+#endif
\ No newline at end of file
diff --git a/TinySTL/TinySTL.vcxproj b/TinySTL/TinySTL.vcxproj
index 8901679..5e1c381 100644
--- a/TinySTL/TinySTL.vcxproj
+++ b/TinySTL/TinySTL.vcxproj
@@ -103,6 +103,7 @@
     <ClCompile Include="Test\StringTest.cpp" />
     <ClCompile Include="Test\SuffixArrayTest.cpp" />
     <ClCompile Include="Test\TrieTreeTest.cpp" />
+    <ClCompile Include="Test\UFSetTest.cpp" />
     <ClCompile Include="Test\UniquePtrTest.cpp" />
     <ClCompile Include="Test\Unordered_setTest.cpp" />
     <ClCompile Include="Test\VectorTest.cpp" />
@@ -159,11 +160,13 @@
     <ClInclude Include="Test\SuffixArrayTest.h" />
     <ClInclude Include="Test\TestUtil.h" />
     <ClInclude Include="Test\TrieTreeTest.h" />
+    <ClInclude Include="Test\UFSetTest.h" />
     <ClInclude Include="Test\UniquePtrTest.h" />
     <ClInclude Include="Test\Unordered_setTest.h" />
     <ClInclude Include="Test\VectorTest.h" />
     <ClInclude Include="TrieTree.h" />
     <ClInclude Include="TypeTraits.h" />
+    <ClInclude Include="UFSet.h" />
     <ClInclude Include="UninitializedFunctions.h" />
     <ClInclude Include="Unordered_set.h" />
     <ClInclude Include="Utility.h" />
diff --git a/TinySTL/TinySTL.vcxproj.filters b/TinySTL/TinySTL.vcxproj.filters
index 166fc97..02e2c24 100644
--- a/TinySTL/TinySTL.vcxproj.filters
+++ b/TinySTL/TinySTL.vcxproj.filters
@@ -108,6 +108,9 @@
     <ClCompile Include="Test\COWPtrTest.cpp">
       <Filter>Test</Filter>
     </ClCompile>
+    <ClCompile Include="Test\UFSetTest.cpp">
+      <Filter>Test</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="TypeTraits.h">
@@ -290,6 +293,12 @@
     <ClInclude Include="Test\COWPtrTest.h">
       <Filter>Test</Filter>
     </ClInclude>
+    <ClInclude Include="Test\UFSetTest.h">
+      <Filter>Test</Filter>
+    </ClInclude>
+    <ClInclude Include="UFSet.h">
+      <Filter>头文件</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <None Include="..\README.md" />
diff --git a/TinySTL/UFSet.h b/TinySTL/UFSet.h
new file mode 100644
index 0000000..d00af29
--- /dev/null
+++ b/TinySTL/UFSet.h
@@ -0,0 +1,53 @@
+#ifndef _UF_SET_H_
+#define _UF_SET_H_
+
+#include <cstring>
+
+namespace TinySTL{
+	template <size_t N>
+	class uf_set{
+	public:
+		uf_set();
+
+		int Find(int index);
+		void Union(int index1, int index2);
+
+		void Clear();
+	private:
+		int parent[N];//parent[i] = -n ±íʾ½ÚµãiÊǸù½ÚµãÇÒÒÔiΪ¸ùµÄÊ÷Öй²ÓÐn¸ö½Úµã
+	};
+
+	template<size_t N>
+	uf_set<N>::uf_set(){
+		Clear();
+	}
+	template<size_t N>
+	int uf_set<N>::Find(int index){
+		auto root = index;
+		for (; parent[root] >= 0; root = parent[root]){}
+		while (root != index){//·¾¶Ñ¹Ëõ
+			auto t = parent[index];
+			parent[index] = root;
+			index = t;
+		}
+		return root;
+	}
+	template<size_t N>
+	void uf_set<N>::Union(int index1, int index2){
+		auto root1 = Find(index1), root2 = Find(index2);
+		auto total_nodes = parent[root1] + parent[root2];//total nodes
+		if (parent[root1] > parent[root2]){//¼ÓȨºÏ²¢
+			parent[root1] = root2;
+			parent[root2] = total_nodes;
+		}else{
+			parent[root2] = root1;
+			parent[root1] = total_nodes;
+		}
+	}
+	template<size_t N>
+	void uf_set<N>::Clear(){
+		memset(parent, -1, sizeof(int) * N);
+	}
+}
+
+#endif
\ No newline at end of file
diff --git a/TinySTL/main.cpp b/TinySTL/main.cpp
index 4c8bd60..df3e100 100644
--- a/TinySTL/main.cpp
+++ b/TinySTL/main.cpp
@@ -21,6 +21,7 @@
 #include "Test\StringTest.h"
 #include "Test\SuffixArrayTest.h"
 #include "Test\TrieTreeTest.h"
+#include "Test\UFSetTest.h"
 #include "Test\UniquePtrTest.h"
 #include "Test\Unordered_setTest.h"
 #include "Test\VectorTest.h"
@@ -46,6 +47,7 @@ int main(){
 	TinySTL::StringTest::testAllCases();
 	TinySTL::SuffixArrayTest::testAllCases();
 	TinySTL::TrieTreeTest::testAllCases();
+	TinySTL::UFSetTest::testAllCases();
 	TinySTL::UniquePtrTest::testAllCases();
 	TinySTL::Unordered_setTest::testAllCases();
 	TinySTL::VectorTest::testAllCases();