Created 141-Linked-List-Cycle.cs

Author: qwmhq

csharp/141-Linked-List-Cycle.cs

@@ -0,0 +1,25 @@
+/**
+ * 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 {
+    public bool HasCycle(ListNode head) {
+        ListNode slow = head, fast = head;
+
+        while (fast != null && fast.next != null)
+        {
+            fast = fast.next.next;
+            slow = slow.next;
+            if (slow.Equals(fast)) return true;
+        }
+        return false;
+    }
+}