Add solution #374

Author: JoshCrozier

README.md

@@ -105,6 +105,7 @@
 347|[Top K Frequent Elements](./0347-top-k-frequent-elements.js)|Medium|
 349|[Intersection of Two Arrays](./0349-intersection-of-two-arrays.js)|Easy|
 350|[Intersection of Two Arrays II](./0350-intersection-of-two-arrays-ii.js)|Easy|
+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|
 442|[Find All Duplicates in an Array](./0442-find-all-duplicates-in-an-array.js)|Medium|

solutions/0374-guess-number-higher-or-lower.js

@@ -0,0 +1,46 @@
+/**
+ * 374. Guess Number Higher or Lower
+ * https://leetcode.com/problems/guess-number-higher-or-lower/
+ * Difficulty: Medium
+ *
+ * We are playing the Guess Game. The game is as follows:
+ *
+ * I pick a number from 1 to n. You have to guess which number I picked.
+ *
+ * Every time you guess wrong, I will tell you whether the number I picked is higher
+ * or lower than your guess.
+ *
+ * You call a pre-defined API int guess(int num), which returns 3 possible results:
+ * - -1: The number I picked is lower than your guess (i.e. pick < num).
+ * - 1: The number I picked is higher than your guess (i.e. pick > num).
+ * - 0: The number I picked is equal to your guess (i.e. pick == num).
+ *
+ * Return the number that I picked.
+ */
+
+/**
+ * Forward declaration of guess API.
+ * @param {number} num   your guess
+ * @return 	            -1 if num is lower than the guess number
+ *			             1 if num is higher than the guess number
+ *                       otherwise return 0
+ * var guess = function(num) {}
+ */
+
+/**
+ * @param {number} n
+ * @return {number}
+ */
+var guessNumber = function(n) {
+  let left = 1;
+  let right = n;
+
+  while (left <= right) {
+    const pivot = Math.floor((right + left) / 2);
+    switch (guess(pivot)) {
+      case -1: right = pivot - 1; break;
+      case 1: left = pivot + 1; break;
+      case 0: return pivot;
+    }
+  }
+};