diff --git a/.gitignore b/.gitignore
index 093a5330f8e03146eeb7a0375dd065eade4b284a..cd1fbccc7b2338abd260534eb937dddd3eab9d1a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,4 +5,3 @@ db.json
 node_modules/
 public/
 .deploy*/
-.idea*
diff --git a/.idea/workspace.xml b/.idea/workspace.xml
new file mode 100644
index 0000000000000000000000000000000000000000..3dad957bc2423b67bfcb9b4e3ac5ba6426bea616
--- /dev/null
+++ b/.idea/workspace.xml
@@ -0,0 +1,351 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ChangeListManager">
+    <list default="true" id="80ba8fc3-bd76-40d2-9857-288be3295a43" name="Default Changelist" comment="">
+      <change beforePath="$PROJECT_DIR$/docs/Leetcode_Solutions/Java/0004._Median_of_Two_Sorted_Arrays.md" beforeDir="false" afterPath="$PROJECT_DIR$/docs/Leetcode_Solutions/Java/0004._Median_of_Two_Sorted_Arrays.md" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/docs/Leetcode_Solutions/Java/0005._Longest_Palindromic_Substring" beforeDir="false" />
+    </list>
+    <option name="EXCLUDED_CONVERTED_TO_IGNORED" value="true" />
+    <option name="SHOW_DIALOG" value="false" />
+    <option name="HIGHLIGHT_CONFLICTS" value="true" />
+    <option name="HIGHLIGHT_NON_ACTIVE_CHANGELIST" value="false" />
+    <option name="LAST_RESOLUTION" value="IGNORE" />
+  </component>
+  <component name="FileEditorManager">
+    <leaf>
+      <file pinned="false" current-in-tab="false">
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+          <provider selected="true" editor-type-id="split-provider[text-editor;markdown-preview-editor]">
+            <state split_layout="FIRST">
+              <first_editor />
+              <second_editor />
+            </state>
+          </provider>
+        </entry>
+      </file>
+      <file pinned="false" current-in-tab="true">
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+          <provider selected="true" editor-type-id="split-provider[text-editor;markdown-preview-editor]">
+            <state split_layout="FIRST">
+              <first_editor relative-caret-position="501">
+                <caret line="37" lean-forward="true" selection-start-line="37" selection-end-line="37" />
+              </first_editor>
+              <second_editor />
+            </state>
+          </provider>
+        </entry>
+      </file>
+      <file pinned="false" current-in-tab="false">
+        <entry file="file://$PROJECT_DIR$/docs/Leetcode_Solutions/Java/0003._Longest_Substring_Without_Repeating_Characters.md">
+          <provider selected="true" editor-type-id="split-provider[text-editor;markdown-preview-editor]">
+            <state split_layout="SPLIT">
+              <first_editor />
+              <second_editor />
+            </state>
+          </provider>
+        </entry>
+      </file>
+      <file pinned="false" current-in-tab="false">
+        <entry file="file://$PROJECT_DIR$/docs/Leetcode_Solutions/Java/0005._Longest_Palindromic_Substring.md">
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+              </first_editor>
+              <second_editor />
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+          </provider>
+        </entry>
+      </file>
+      <file pinned="false" current-in-tab="false">
+        <entry file="file://$PROJECT_DIR$/docs/Leetcode_Solutions/Java/0793._Preimage_Size_of_Factorial_Zeroes_Function.md">
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+              <first_editor relative-caret-position="152">
+                <caret line="8" column="4" selection-start-line="8" selection-end-line="8" selection-end-column="4" />
+              </first_editor>
+              <second_editor />
+            </state>
+          </provider>
+        </entry>
+      </file>
+      <file pinned="false" current-in-tab="false">
+        <entry file="file://$PROJECT_DIR$/docs/Leetcode_Solutions/Java/0141._linked_list_cycle.md">
+          <provider selected="true" editor-type-id="split-provider[text-editor;markdown-preview-editor]">
+            <state split_layout="FIRST">
+              <first_editor />
+              <second_editor />
+            </state>
+          </provider>
+        </entry>
+      </file>
+    </leaf>
+  </component>
+  <component name="Git.Settings">
+    <option name="RECENT_GIT_ROOT_PATH" value="$PROJECT_DIR$" />
+  </component>
+  <component name="IdeDocumentHistory">
+    <option name="CHANGED_PATHS">
+      <list>
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+        <option value="$PROJECT_DIR$/docs/Leetcode_Solutions/Java/0005._Longest_Palindromic_Substring.md" />
+        <option value="$PROJECT_DIR$/docs/Leetcode_Solutions/Java/0004._Median_of_Two_Sorted_Arrays.md" />
+      </list>
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+  <component name="ProjectFrameBounds">
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+    <option name="height" value="951" />
+  </component>
+  <component name="ProjectView">
+    <navigator proportions="" version="1">
+      <foldersAlwaysOnTop value="true" />
+    </navigator>
+    <panes>
+      <pane id="ProjectPane">
+        <subPane>
+          <expand>
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+              <item name="awesome-algorithm" type="b2602c69:ProjectViewProjectNode" />
+              <item name="awesome-algorithm" type="462c0819:PsiDirectoryNode" />
+            </path>
+            <path>
+              <item name="awesome-algorithm" type="b2602c69:ProjectViewProjectNode" />
+              <item name="awesome-algorithm" type="462c0819:PsiDirectoryNode" />
+              <item name="docs" type="462c0819:PsiDirectoryNode" />
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+            <path>
+              <item name="awesome-algorithm" type="b2602c69:ProjectViewProjectNode" />
+              <item name="awesome-algorithm" type="462c0819:PsiDirectoryNode" />
+              <item name="docs" type="462c0819:PsiDirectoryNode" />
+              <item name="Leetcode_Solutions" type="462c0819:PsiDirectoryNode" />
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+              <item name="awesome-algorithm" type="462c0819:PsiDirectoryNode" />
+              <item name="docs" type="462c0819:PsiDirectoryNode" />
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+      <pane id="PackagesPane" />
+      <pane id="Scope" />
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+    <property name="project.structure.proportion" value="0.0" />
+    <property name="project.structure.side.proportion" value="0.0" />
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+  <component name="RunDashboard">
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+  <component name="SvnConfiguration">
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+  <component name="TaskManager">
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+      <changelist id="80ba8fc3-bd76-40d2-9857-288be3295a43" name="Default Changelist" comment="" />
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+      <option name="presentableId" value="Default" />
+      <updated>1556856184639</updated>
+      <workItem from="1556856187222" duration="1720000" />
+    </task>
+    <servers />
+  </component>
+  <component name="TimeTrackingManager">
+    <option name="totallyTimeSpent" value="1720000" />
+  </component>
+  <component name="ToolWindowManager">
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+    <editor active="true" />
+    <layout>
+      <window_info id="Image Layers" />
+      <window_info id="Designer" />
+      <window_info id="UI Designer" />
+      <window_info id="Capture Tool" />
+      <window_info id="Favorites" side_tool="true" />
+      <window_info active="true" content_ui="combo" id="Project" order="0" visible="true" weight="0.30773956" />
+      <window_info id="Structure" order="1" side_tool="true" weight="0.25" />
+      <window_info anchor="bottom" id="Docker" show_stripe_button="false" />
+      <window_info anchor="bottom" id="Database Changes" />
+      <window_info anchor="bottom" id="Version Control" />
+      <window_info anchor="bottom" id="Terminal" />
+      <window_info anchor="bottom" id="Event Log" side_tool="true" />
+      <window_info anchor="bottom" id="Message" order="0" />
+      <window_info anchor="bottom" id="Find" order="1" />
+      <window_info anchor="bottom" id="Run" order="2" />
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+      <window_info anchor="bottom" id="Inspection" order="5" weight="0.4" />
+      <window_info anchor="bottom" id="TODO" order="6" />
+      <window_info anchor="right" id="Palette" />
+      <window_info anchor="right" id="Theme Preview" />
+      <window_info anchor="right" id="Maven" />
+      <window_info anchor="right" id="Capture Analysis" />
+      <window_info anchor="right" id="Palette&#9;" />
+      <window_info anchor="right" id="Database" />
+      <window_info anchor="right" id="Commander" internal_type="SLIDING" order="0" type="SLIDING" weight="0.4" />
+      <window_info anchor="right" id="Ant Build" order="1" weight="0.25" />
+      <window_info anchor="right" content_ui="combo" id="Hierarchy" order="2" weight="0.25" />
+    </layout>
+  </component>
+  <component name="TypeScriptGeneratedFilesManager">
+    <option name="version" value="1" />
+  </component>
+  <component name="editorHistoryManager">
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+      <provider selected="true" editor-type-id="split-provider[text-editor;markdown-preview-editor]">
+        <state split_layout="FIRST">
+          <first_editor />
+          <second_editor />
+        </state>
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+      <provider selected="true" editor-type-id="split-provider[text-editor;markdown-preview-editor]">
+        <state split_layout="FIRST">
+          <first_editor relative-caret-position="152">
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+      </provider>
+    </entry>
+    <entry file="file://$PROJECT_DIR$/docs/Leetcode_Solutions/Java/0001._Two_Sum.md">
+      <provider selected="true" editor-type-id="split-provider[text-editor;markdown-preview-editor]">
+        <state split_layout="FIRST">
+          <first_editor />
+          <second_editor />
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+      </provider>
+    </entry>
+    <entry file="file://$PROJECT_DIR$/docs/Leetcode_Solutions/Java/0002._add_two_numbers.md">
+      <provider selected="true" editor-type-id="split-provider[text-editor;markdown-preview-editor]">
+        <state split_layout="FIRST">
+          <first_editor relative-caret-position="38">
+            <caret line="2" column="28" selection-start-line="2" selection-start-column="22" selection-end-line="2" selection-end-column="28" />
+          </first_editor>
+          <second_editor />
+        </state>
+      </provider>
+    </entry>
+    <entry file="file://$PROJECT_DIR$/.gitignore">
+      <provider selected="true" editor-type-id="text-editor">
+        <state relative-caret-position="133">
+          <caret line="7" column="6" selection-start-line="7" selection-start-column="6" selection-end-line="7" selection-end-column="6" />
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+    </entry>
+    <entry file="file://$PROJECT_DIR$/docs/Leetcode_Solutions/Java/0003._Longest_Substring_Without_Repeating_Characters.md">
+      <provider selected="true" editor-type-id="split-provider[text-editor;markdown-preview-editor]">
+        <state split_layout="SPLIT">
+          <first_editor />
+          <second_editor />
+        </state>
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+      <provider selected="true" editor-type-id="split-provider[text-editor;markdown-preview-editor]">
+        <state split_layout="FIRST">
+          <first_editor relative-caret-position="1482">
+            <caret line="78" selection-start-line="78" selection-end-line="78" />
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+          <second_editor />
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+      <provider selected="true" editor-type-id="split-provider[text-editor;markdown-preview-editor]">
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+          <second_editor />
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+    </entry>
+  </component>
+  <component name="masterDetails">
+    <states>
+      <state key="GlobalLibrariesConfigurable.UI">
+        <settings>
+          <splitter-proportions>
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+              <list>
+                <option value="0.2" />
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+      </state>
+      <state key="JdkListConfigurable.UI">
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+      <state key="ProjectJDKs.UI">
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+      <state key="ProjectLibrariesConfigurable.UI">
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+      <state key="ScopeChooserConfigurable.UI">
+        <settings>
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+              <list>
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+          </splitter-proportions>
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+      </state>
+    </states>
+  </component>
+</project>
\ No newline at end of file