valid palindrome solution

Author: bhan

valid-palindrome/byol-han.js

@@ -0,0 +1,32 @@
+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+
+// 1. Two Pointers
+// time complexity: O(n)
+// space complexity: O(1)
+var isPalindrome = function (s) {
+  let sRefine = s.toLowerCase().replace(/[^a-z0-9]/g, "");
+  let left = 0;
+  let right = sRefine.length - 1;
+
+  while (left < right) {
+    if (sRefine[left] !== sRefine[right]) {
+      return false;
+    }
+    left++;
+    right--;
+  }
+
+  return true;
+};
+
+// 2. String Manipulation
+// time complexity: O(n)
+// space complexity: O(n)
+var isPalindrome = function (s) {
+  let refined = s.toLowerCase().replace(/[^a-z0-9]/g, "");
+  let reversed = refined.split("").reverse().join("");
+  return refined === reversed;
+};