Merge pull request #678 from choidabom/main

[choidabom] Week 1

Author: choidabom

contains-duplicate/choidabom.js

@@ -0,0 +1,17 @@
+/**
+ * Runtime: 17ms, Memory: 63.18MB
+ * 
+ * Time Complexity: O(n)
+ *  - Array to Set takes O(n)
+ *  - Compare Set size and array length takes O(1)
+ * Space Complexity: O(n)
+ *  - Space for Set : O(n)
+*/
+
+/**
+ * @param {number[]} nums
+ * @return {boolean}
+ */
+var containsDuplicate = function(nums) {
+    return new Set(nums).size !== nums.length
+};

valid-palindrome/choidabom.js

@@ -0,0 +1,28 @@
+/**
+ * Runtime: 7ms, Memory: 55.02MB
+ * 
+ * Time Complexity: O(n)
+ * Space Complexity: O(n)
+*/
+
+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+function isPalindrome(s) {
+	const alphanumeric = getAlphanumeric(s)
+	return alphanumeric === alphanumeric.split("").reverse().join("")
+}
+
+function getAlphanumeric(string) {
+    const number = /[0-9]/
+    const alphabet = /[a-zA-Z]/
+	let alphanumeric = []
+    
+	for (const str of string) {
+		if (number.test(str) || alphabet.test(str)) {
+			alphanumeric.push(str)
+		}
+	}
+	return alphanumeric.join("").toLowerCase()
+}