Add Valid Palindrome C#

August-LeetCoding-Challenge/03-Valid-Palindrome/Valid-Palindrome.cs

@@ -0,0 +1,20 @@
+public class Solution {
+    public bool IsPalindrome(string s) {
+        int begin = 0;
+        int end = s.Length-1;
+        while(begin <= end){
+            while(begin<=end && !Char.IsLetterOrDigit(s[begin])){
+                begin++;
+            }
+            while(begin<=end && !Char.IsLetterOrDigit(s[end])){
+                end--;
+            }
+            if(begin<=end && Char.ToLower(s[begin]) != Char.ToLower(s[end])){
+                return false;
+            }
+            begin++;
+            end--;
+        }
+        return true;
+    }
+}

README.md

@@ -2,14 +2,14 @@
 
 https://leetcode.com
 
-
 ## August LeetCoding Challenge
 Click [here](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge/) for problem descriptions.
 
 Solutions in various programming languages are provided. Enjoy it.
 
 1. [Detect Capital](https://github.com/AlgoStudyGroup/Leetcode/tree/master/August-LeetCoding-Challenge/01-Detect-Capital)
 2. [Design HashSet](https://github.com/AlgoStudyGroup/Leetcode/tree/master/August-LeetCoding-Challenge/02-Design-HashSet)
+3. [Valid Palindrome](https://github.com/AlgoStudyGroup/Leetcode/tree/master/August-LeetCoding-Challenge/03-Valid-Palindrome)
 
 ## July LeetCoding Challenge
 Click [here](https://leetcode.com/explore/featured/card/july-leetcoding-challenge/) for problem descriptions.