Valid Palindrome

Author: Sunjae95

valid-palindrome/sunjae95.js

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+/**
+ * @description
+ * brainstorming:
+ * string method + two pointer
+ *
+ * time complexity: O(n)
+ * space complexity: O(n)
+ */
+
+var isPalindrome = function (s) {
+  const asciiArray = [];
+
+  for (let i = 0; i < s.length; i++) {
+    const asciiCode = s[i].toLowerCase().charCodeAt(0);
+    const isNumber = asciiCode >= 48 && asciiCode <= 57;
+    const isLowerCase = asciiCode >= 97 && asciiCode <= 122;
+
+    if (isNumber || isLowerCase) asciiArray.push(asciiCode);
+  }
+
+  const len = asciiArray.length;
+  const middleIndex = Math.floor(len);
+
+  for (let i = 0; i < middleIndex; i++) {
+    if (asciiArray[i] !== asciiArray[len - i - 1]) return false;
+  }
+
+  return true;
+};