Merge pull request neetcode-gh#1946 from thuanle123/680-valid-palindrome-ii

create 680. Valid Palindrome II c#

Author: tahsintunan

csharp/0680-valid-palindrome-ii.cs

@@ -0,0 +1,31 @@
+public class Solution
+{
+    public bool ValidPalindrome(string s)
+    {
+        int leftPointer = 0;
+        int rightPointer = s.Length - 1;
+        while (leftPointer < rightPointer)
+        {
+            if (s[leftPointer] != s[rightPointer])
+            {
+                return IsPalindrome(s, leftPointer + 1, rightPointer) || IsPalindrome(s, leftPointer, rightPointer - 1);
+            }
+            leftPointer++;
+            rightPointer--;
+        }
+        return true;
+    }
+    public bool IsPalindrome(String s, int leftPointer, int rightPointer)
+    {
+        while (leftPointer < rightPointer)
+        {
+            if (s[leftPointer] != s[rightPointer])
+            {
+                return false;
+            }
+            leftPointer++;
+            rightPointer--;
+        }
+        return true;
+    }
+}