palindromic-substrings solution

Author: Moonjonghoo

palindromic-substrings/moonjonghoo.js

@@ -0,0 +1,22 @@
+/**
+ * @param {string} s
+ * @return {number}
+ */
+var countSubstrings = function (s) {
+  let count = 0;
+
+  const expand = (left, right) => {
+    while (left >= 0 && right < s.length && s[left] === s[right]) {
+      count++;
+      left--;
+      right++;
+    }
+  };
+
+  for (let i = 0; i < s.length; i++) {
+    expand(i, i); // 홀수 길이 중심 (예: "aba")
+    expand(i, i + 1); // 짝수 길이 중심 (예: "aa")
+  }
+
+  return count;
+};