diff --git a/.idea/.idea.LeetCodeSharp/.idea/.gitignore b/.idea/.idea.LeetCodeSharp/.idea/.gitignore
new file mode 100644
index 0000000..2cfe808
--- /dev/null
+++ b/.idea/.idea.LeetCodeSharp/.idea/.gitignore
@@ -0,0 +1,13 @@
+# 默认忽略的文件
+/shelf/
+/workspace.xml
+# Rider 忽略的文件
+/contentModel.xml
+/.idea.LeetCodeSharp.iml
+/modules.xml
+/projectSettingsUpdater.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/.idea.LeetCodeSharp/.idea/encodings.xml b/.idea/.idea.LeetCodeSharp/.idea/encodings.xml
new file mode 100644
index 0000000..df87cf9
--- /dev/null
+++ b/.idea/.idea.LeetCodeSharp/.idea/encodings.xml
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Encoding" addBOMForNewFiles="with BOM under Windows, with no BOM otherwise" />
+</project>
\ No newline at end of file
diff --git a/.idea/.idea.LeetCodeSharp/.idea/indexLayout.xml b/.idea/.idea.LeetCodeSharp/.idea/indexLayout.xml
new file mode 100644
index 0000000..7b08163
--- /dev/null
+++ b/.idea/.idea.LeetCodeSharp/.idea/indexLayout.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="UserContentModel">
+    <attachedFolders />
+    <explicitIncludes />
+    <explicitExcludes />
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/.idea.LeetCodeSharp/.idea/vcs.xml b/.idea/.idea.LeetCodeSharp/.idea/vcs.xml
new file mode 100644
index 0000000..35eb1dd
--- /dev/null
+++ b/.idea/.idea.LeetCodeSharp/.idea/vcs.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/LeetCodeSharp/Problems/Solution141.cs b/LeetCodeSharp/Problems/Solution141.cs
new file mode 100644
index 0000000..056b38a
--- /dev/null
+++ b/LeetCodeSharp/Problems/Solution141.cs
@@ -0,0 +1,46 @@
+// [141] Linked List Cycle
+
+using System.Collections.Generic;
+using LeetCodeSharp.Utils;
+
+namespace LeetCodeSharp.Problems141
+{
+    // Submission codes start here
+
+    /**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ *     public int val;
+ *     public ListNode next;
+ *     public ListNode(int x) {
+ *         val = x;
+ *         next = null;
+ *     }
+ * }
+ */
+    public class Solution
+    {
+        private readonly HashSet<ListNode> _visited = new HashSet<ListNode>();
+
+        public bool HasCycle(ListNode head)
+        {
+            _visited.Clear();
+            ListNode node = head;
+
+            while (node != null)
+            {
+                if (_visited.Contains(node))
+                {
+                    return true;
+                }
+
+                _visited.Add(node);
+                node = node.next;
+            }
+
+            return false;
+        }
+    }
+
+    // Submission codes end here
+}
\ No newline at end of file
diff --git a/commit.sh b/commit.sh
new file mode 100755
index 0000000..506d674
--- /dev/null
+++ b/commit.sh
@@ -0,0 +1,11 @@
+#!/bin/sh
+
+set -e
+
+time=$(date "+%Y%m%d")
+message="$time Finished"
+
+git add -A
+git commit -m "$message"
+
+git push