ignore non-alphanumeric

Author: furahadamien

Others/Palindrome.java

@@ -22,4 +22,29 @@ public boolean SecondWay(String x) {
 
         return SecondWay(x.substring(1, x.length() - 1));
     }
+
+    /**
+     * This method ignores all non-alphanumeric characters and case runs in O(n)
+     * where n is the length of s
+     * 
+     * @param s String to check
+     * @return true if s is palindrome else false
+     */
+    public boolean isPalindrome(String s) {
+        s = s.toLowerCase().trim();
+        StringBuilder sb = new StringBuilder();
+        for (char c : s.toCharArray()) {
+            if (Character.isLetter(c) || Character.isDigit(c))
+                sb.append(c);
+        }
+        s = sb.toString();
+        int start = 0;
+        int end = s.length() - 1;
+        while (start <= end) {
+            if (s.charAt(start++) != s.charAt(end--))
+                return false;
+
+        }
+        return true;
+    }
 }