add solution valid palindrome

Author: rivkode

valid-palindrome/JonghunLee.py

@@ -0,0 +1,51 @@
+import re
+
+
+# Time Complexity O(n)
+# - Both normal preprocessing and two-pointer comparisons have time complexity proportional to the length of the input string.
+# Space Complexity O(n)
+# - The space of the new string joined_string preprocessed from the input string is proportional to the length of the input string.
+
+class Solution:
+    def isPalindrome(self, s: str) -> bool:
+        # Pre-processing using regular expression
+        joined_string = re.sub(r"[^a-zA-Z]", "", s.lower())
+        str_length = len(joined_string)
+
+
+        # for loop n/2, two pointer for verify same or not
+        for i in range(str_length // 2):
+            end = str_length - i - 1
+            if not self.check_palindrome(i, end, joined_string):
+                return False
+
+        return True
+
+    def check_palindrome(self, i, end, joined_string) -> bool:
+        left = joined_string[i]
+        right = joined_string[end]
+
+        if left == right:
+            return True
+        else:
+            return False
+
+if __name__ == "__main__":
+    solution = Solution()
+
+    # test case
+    test_string = [
+        "A man, a plan, a canal: Panama",  # True (회문)
+        "race a car",  # False (회문 아님)
+        " ",  # True (빈 문자열도 회문으로 간주)
+        "abba",  # True (회문)
+        "abcba",  # True (회문)
+    ]
+
+    for index, test in enumerate(test_string):
+        print(f"start {index} test")
+        print(f"input : {test}")
+        print(f"Is valid palindrome ? {solution.isPalindrome(test)}\n")
+
+
+