[LC] feat: palindromic-substring

Author: HaJunYoo

palindromic-substrings/hajunyoo.py

@@ -0,0 +1,18 @@
+class Solution:
+    def countSubstrings(self, s: str) -> int:
+        self.count = 0
+        n = len(s)
+
+        def two_pointer_expand(left, right):
+            while left >= 0 and right < n and s[left] == s[right]:
+                self.count += 1
+                left -= 1
+                right += 1
+
+        for i in range(0, n):
+            # 1, 3, 5 ...
+            two_pointer_expand(i, i)
+            # 2, 4, 6 ...
+            two_pointer_expand(i, i + 1)
+
+        return self.count