commit

Author: bryanfks-dev

125. Valid Palindrome.java

@@ -0,0 +1,39 @@
+class Solution {
+    public boolean isPalindrome(String s) {
+        // Base case
+        if (s.isEmpty())
+            return true;
+
+        // Two pointer method
+        int l = 0;
+        int r = s.length() - 1;
+
+        while (l < r) {
+            // Move l untill find a letter or number
+            while (l < r && !Character.isLetterOrDigit(s.charAt(l)))
+                l++;
+
+            // Move r untill find a letter or number
+            while (l < r && !Character.isLetterOrDigit(s.charAt(r)))
+                r--;
+            
+            char l_ch = s.charAt(l);
+            char r_ch = s.charAt(r);
+
+            if (l_ch >= 'A' && l_ch <= 'Z')
+                l_ch = (char)(l_ch + 32);
+            
+            if (r_ch >= 'A' && r_ch <= 'Z')
+                r_ch = (char)(r_ch + 32);
+
+            // Check if letter in l and r are matches
+            if (l_ch != r_ch)
+                return false;
+
+            l++;
+            r--;
+        }
+
+        return true;
+    }
+}