solve: palindromic substrings

Author: sounmind

palindromic-substrings/evan.py

@@ -0,0 +1,21 @@
+class Solution:
+    def countSubstrings(self, s: str) -> int:
+        def expand_around_center(left: int, right: int) -> int:
+            count = 0
+
+            while left >= 0 and right < len(s) and s[left] == s[right]:
+                count += 1
+                left -= 1
+                right += 1
+
+            return count
+
+        total_count = 0
+
+        for i in range(len(s)):
+            # Odd-length palindromes (single character(s[i]) center)
+            total_count += expand_around_center(i, i)
+            # Even-length palindromes (two character(s[i], s[i+1])s center)
+            total_count += expand_around_center(i, i + 1)
+
+        return total_count