diff --git a/.idea/.gitignore b/.idea/.gitignore
new file mode 100644
index 00000000..35410cac
--- /dev/null
+++ b/.idea/.gitignore
@@ -0,0 +1,8 @@
+# 默认忽略的文件
+/shelf/
+/workspace.xml
+# 基于编辑器的 HTTP 客户端请求
+/httpRequests/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml
diff --git a/.idea/encodings.xml b/.idea/encodings.xml
new file mode 100644
index 00000000..c2bae49d
--- /dev/null
+++ b/.idea/encodings.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Encoding" defaultCharsetForPropertiesFiles="UTF-8">
+    <file url="PROJECT" charset="UTF-8" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/inspectionProfiles/Project_Default.xml b/.idea/inspectionProfiles/Project_Default.xml
new file mode 100644
index 00000000..3f19e2d8
--- /dev/null
+++ b/.idea/inspectionProfiles/Project_Default.xml
@@ -0,0 +1,70 @@
+<component name="InspectionProjectProfileManager">
+  <profile version="1.0">
+    <option name="myName" value="Project Default" />
+    <inspection_tool class="PyCompatibilityInspection" enabled="true" level="WARNING" enabled_by_default="true">
+      <option name="ourVersions">
+        <value>
+          <list size="4">
+            <item index="0" class="java.lang.String" itemvalue="2.7" />
+            <item index="1" class="java.lang.String" itemvalue="3.8" />
+            <item index="2" class="java.lang.String" itemvalue="3.9" />
+            <item index="3" class="java.lang.String" itemvalue="3.10" />
+          </list>
+        </value>
+      </option>
+    </inspection_tool>
+    <inspection_tool class="PyPackageRequirementsInspection" enabled="true" level="WARNING" enabled_by_default="true">
+      <option name="ignoredPackages">
+        <value>
+          <list size="26">
+            <item index="0" class="java.lang.String" itemvalue="xdoctest" />
+            <item index="1" class="java.lang.String" itemvalue="opencv-python" />
+            <item index="2" class="java.lang.String" itemvalue="chainercv" />
+            <item index="3" class="java.lang.String" itemvalue="lxml" />
+            <item index="4" class="java.lang.String" itemvalue="fastrlock" />
+            <item index="5" class="java.lang.String" itemvalue="Pillow" />
+            <item index="6" class="java.lang.String" itemvalue="cuda9.0" />
+            <item index="7" class="java.lang.String" itemvalue="pytorch0.4.1" />
+            <item index="8" class="java.lang.String" itemvalue="python3.5" />
+            <item index="9" class="java.lang.String" itemvalue="cudnn7.1.3" />
+            <item index="10" class="java.lang.String" itemvalue="scipy" />
+            <item index="11" class="java.lang.String" itemvalue="pytest" />
+            <item index="12" class="java.lang.String" itemvalue="mmlvis" />
+            <item index="13" class="java.lang.String" itemvalue="sklearn" />
+            <item index="14" class="java.lang.String" itemvalue="asynctest" />
+            <item index="15" class="java.lang.String" itemvalue="flake8" />
+            <item index="16" class="java.lang.String" itemvalue="albumentations" />
+            <item index="17" class="java.lang.String" itemvalue="imagecorruptions" />
+            <item index="18" class="java.lang.String" itemvalue="onnxruntime" />
+            <item index="19" class="java.lang.String" itemvalue="interrogate" />
+            <item index="20" class="java.lang.String" itemvalue="isort" />
+            <item index="21" class="java.lang.String" itemvalue="kwarray" />
+            <item index="22" class="java.lang.String" itemvalue="onnx" />
+            <item index="23" class="java.lang.String" itemvalue="codecov" />
+            <item index="24" class="java.lang.String" itemvalue="ubelt" />
+            <item index="25" class="java.lang.String" itemvalue="pydensecrf" />
+          </list>
+        </value>
+      </option>
+    </inspection_tool>
+    <inspection_tool class="PyPep8NamingInspection" enabled="true" level="WEAK WARNING" enabled_by_default="true">
+      <option name="ignoredErrors">
+        <list>
+          <option value="N806" />
+          <option value="N802" />
+          <option value="N803" />
+        </list>
+      </option>
+    </inspection_tool>
+    <inspection_tool class="PyUnresolvedReferencesInspection" enabled="true" level="WARNING" enabled_by_default="true">
+      <option name="ignoredIdentifiers">
+        <list>
+          <option value="tensorflow_core._api.v2.train.exponential_decay" />
+          <option value="mypackage.__all__" />
+          <option value="StudentManagerSystem.main.managerSystem" />
+          <option value="str.tif" />
+        </list>
+      </option>
+    </inspection_tool>
+  </profile>
+</component>
\ No newline at end of file
diff --git a/.idea/inspectionProfiles/profiles_settings.xml b/.idea/inspectionProfiles/profiles_settings.xml
new file mode 100644
index 00000000..105ce2da
--- /dev/null
+++ b/.idea/inspectionProfiles/profiles_settings.xml
@@ -0,0 +1,6 @@
+<component name="InspectionProjectProfileManager">
+  <settings>
+    <option name="USE_PROJECT_PROFILE" value="false" />
+    <version value="1.0" />
+  </settings>
+</component>
\ No newline at end of file
diff --git a/.idea/leetcode-master.iml b/.idea/leetcode-master.iml
new file mode 100644
index 00000000..d0876a78
--- /dev/null
+++ b/.idea/leetcode-master.iml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="PYTHON_MODULE" version="4">
+  <component name="NewModuleRootManager">
+    <content url="file://$MODULE_DIR$" />
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>
\ No newline at end of file
diff --git a/.idea/misc.xml b/.idea/misc.xml
new file mode 100644
index 00000000..8ca8e3b1
--- /dev/null
+++ b/.idea/misc.xml
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectRootManager" version="2" project-jdk-name="Python 3.8" project-jdk-type="Python SDK" />
+  <component name="PyPackaging">
+    <option name="earlyReleasesAsUpgrades" value="true" />
+  </component>
+  <component name="SshConsoleOptionsProvider">
+    <option name="myEncoding" value="UTF-8" />
+    <option name="myConnectionType" value="NONE" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/modules.xml b/.idea/modules.xml
new file mode 100644
index 00000000..7c250acd
--- /dev/null
+++ b/.idea/modules.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/.idea/leetcode-master.iml" filepath="$PROJECT_DIR$/.idea/leetcode-master.iml" />
+    </modules>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/vagrant.xml b/.idea/vagrant.xml
new file mode 100644
index 00000000..a5aa7868
--- /dev/null
+++ b/.idea/vagrant.xml
@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VagrantProjectSettings">
+    <option name="instanceFolder" value="" />
+    <option name="provider" value="" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/vcs.xml b/.idea/vcs.xml
new file mode 100644
index 00000000..94a25f7f
--- /dev/null
+++ b/.idea/vcs.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/problems/0090.子集II.md b/problems/0090.子集II.md
index e85ec66d..d503846e 100644
--- a/problems/0090.子集II.md
+++ b/problems/0090.子集II.md
@@ -261,6 +261,33 @@ class Solution:
             self.path.pop()
 ```
 
+### Python3 
+```python3
+class Solution:
+    def subsetsWithDup(self, nums: List[int]) -> List[List[int]]:
+        res = []
+        path = []
+        nums.sort() # 去重需要先对数组进行排序
+
+        def backtracking(nums, startIndex):
+            # 终止条件
+            res.append(path[:])
+            if startIndex == len(nums):
+                return
+            
+            # for循环
+            for i in range(startIndex, len(nums)):
+                # 数层去重
+                if i > startIndex and nums[i] == nums[i-1]: # 去重
+                    continue
+                path.append(nums[i])
+                backtracking(nums, i+1)
+                path.pop()
+        
+        backtracking(nums, 0)
+        return res
+```
+
 ### Go 
 
 ```Go