Add solution #405

Author: JoshCrozier

0405-convert-a-number-to-hexadecimal.js

@@ -0,0 +1,32 @@
+/**
+ * 405. Convert a Number to Hexadecimal
+ * https://leetcode.com/problems/convert-a-number-to-hexadecimal/
+ * Difficulty: Easy
+ *
+ * Given an integer num, return a string representing its hexadecimal
+ * representation. For negative integers, two’s complement method is used.
+ *
+ * All the letters in the answer string should be lowercase characters,
+ * and there should not be any leading zeros in the answer except for
+ * the zero itself.
+ *
+ * Note: You are not allowed to use any built-in library method to directly
+ * solve this problem.
+ */
+
+/**
+ * @param {number} num
+ * @return {string}
+ */
+var toHex = function(num) {
+  if (num === 0) {
+    return num.toString();
+  }
+  const words = '0123456789abcdef';
+  let result = '';
+  while (num !== 0) {
+    result = words[num & 0xf] + result;
+    num >>>= 4;
+  }
+  return result;
+};

README.md

@@ -163,6 +163,7 @@
 374|[Guess Number Higher or Lower](./0374-guess-number-higher-or-lower.js)|Medium|
 383|[Ransom Note](./0383-ransom-note.js)|Easy|
 387|[First Unique Character in a String](./0387-first-unique-character-in-a-string.js)|Easy|
+405|[Convert a Number to Hexadecimal](./0405-convert-a-number-to-hexadecimal.js)|Easy|
 414|[Third Maximum Number](./0414-third-maximum-number.js)|Easy|
 419|[Battleships in a Board](./0419-battleships-in-a-board.js)|Medium|
 442|[Find All Duplicates in an Array](./0442-find-all-duplicates-in-an-array.js)|Medium|