palindromic substrings

Author: eunhwa99

palindromic-substrings/eunhwa99.java

@@ -0,0 +1,34 @@
+class Solution {
+  public int countSubstrings(String s) {
+    int count = 0;
+    int n = s.length();
+
+    for (int center = 0; center < 2 * n - 1; center++) {
+      int left = center / 2;
+      int right = left + (center % 2); // 홀/짝 팰린드롬 처리
+
+      while (left >= 0 && right < n && s.charAt(left) == s.charAt(right)) {
+        count++;
+        left--;
+        right++;
+      }
+    }
+
+    return count;
+  }
+}
+// Time Complexity: O(n^2)
+// Space Complexity: O(1)
+
+/*
+예시: "abc"
+중심이 문자일 때:
+a (index 0),
+b (index 1),
+c (index 2)
+중심이 문자 사이일 때:
+between a and b
+between b and c
+→ 총 2 * 3 - 1 = 5개의 중심
+*/
+