@@ -0,0 +1,33 @@
+package leetcodeEasyLevel;
+
+public class _0125ValidPalindrome {
+  public static boolean isPalindrome(String s) {
+    //sol1. => Runtime 24ms Memory 40MB
+    //정규식으로 알파벳이 아닌 것들을 없앤다
+    String s1 = s.toLowerCase().replaceAll("[^a-zA-Z0-9]", "");
+    System.out.println(s1);
+
+    //반으로 나눈뒤 글자가 일치하는 지 확인한다.
+    for(int i=0; i<s1.length()/2; i++){
+      if(s1.charAt(i) != s1.charAt(s1.length()-i-1)){
+        return false;
+      }
+    }
+    return true;
+
+    //sol2 => Runtime 39 ms Memory 40.4 MB
+    //one line solution
+    //https://leetcode.com/problems/valid-palindrome/discuss/1008365/Frankenstein's-Function-One-Line-Java-Solution
+    /*
+    return new StringBuilder().append(s).reverse().toString()
+        .replaceAll("[^a-zA-Z0-9]", "").toLowerCase()
+        .equals(s.replaceAll("[^a-zA-Z0-9]", "").toLowerCase()) ? true: false;
+    */
+  }
+
+  public static void main(String[] args) {
+    String s = "A man, a plan, a canal: Panama!!"; //=> t
+              //"race a car" //=> f
+    System.out.println(isPalindrome(s));
+  }
+}