NirmalSilwal · Oct 3, 2020 · Oct 3, 2020
Showing with 47 additions and 0 deletions.

+47 −0 Leetcode/Leetcode_August_Challenge/Valid_Palindrome.java
diff --git a/Leetcode/Leetcode_August_Challenge/Valid_Palindrome.java b/Leetcode/Leetcode_August_Challenge/Valid_Palindrome.java
@@ -0,0 +1,47 @@
+package Leetcode_August_Challenge;
+
+public class Valid_Palindrome {
+
+    public boolean isPalindrome(String s) {
+         // check string if it's null no need to go further direct return false
+
+            if(s==null){
+            return false;
+            }
+
+        // if string contain some char as uppercase or lowercase 
+        // this will convert whole string to lowercase 
+        s = s.toLowerCase();
+
+        // pointed i to intially at 0
+        // and j to end of the string (last character) 
+        int i=0;
+        int j=s.length()-1;
+
+
+        while(i<j){
+            //if i<j and string char contain a-z and 0-9 loop -> true
+
+            while(i<j && !((s.charAt(i)>='a' && s.charAt(i)<='z') 
+                        || (s.charAt(i)>='0'&&s.charAt(i)<='9'))){
+                i++;
+            }
+
+            while(i<j && !((s.charAt(j)>='a' && s.charAt(j)<='z') 
+                        || (s.charAt(j)>='0'&&s.charAt(j)<='9'))){
+                j--;
+            }
+            // if one of string char not match i to j 
+            // it will return false
+            if(s.charAt(i) != s.charAt(j)){
+                return false;
+            }
+
+            i++;
+            j--;
+        }
+     // else return true
+        return true;
+
+        }
+}