Add 125

Author: austinhnelson

Other/125_valid_palindrome.cs

@@ -0,0 +1,29 @@
+using System.Text.RegularExpressions;
+
+public class Solution {
+    public bool IsPalindrome(string s) {
+        // string output = Regex.Replace(s.ToLower(), @"[^a-zA-Z0-9]", "");
+        s = s.ToLower();
+        int leftIndex = 0;
+        int rightIndex = s.Length - 1;
+
+        while(leftIndex < s.Length) {
+            if (!Char.IsLetterOrDigit(s[leftIndex])){
+                leftIndex++;
+                continue;
+            }
+
+            if (!Char.IsLetterOrDigit(s[rightIndex])){
+                rightIndex--;
+                continue;
+            }
+
+            if(s[leftIndex] != s[rightIndex]){
+                return false;
+            }
+            leftIndex++;
+            rightIndex--;
+        }
+        return true;
+    }
+}