Add solution #303

Author: JoshCrozier

README.md

@@ -226,6 +226,7 @@
 283|[Move Zeroes](./0283-move-zeroes.js)|Easy|
 290|[Word Pattern](./0290-word-pattern.js)|Easy|
 295|[Find Median from Data Stream](./0295-find-median-from-data-stream.js)|Hard|
+303|[Range Sum Query - Immutable](./0303-range-sum-query-immutable.js)|Easy|
 316|[Remove Duplicate Letters](./0316-remove-duplicate-letters.js)|Medium|
 322|[Coin Change](./0322-coin-change.js)|Medium|
 326|[Power of Three](./0326-power-of-three.js)|Easy|

solutions/0303-range-sum-query-immutable.js

@@ -0,0 +1,31 @@
+/**
+ * 303. Range Sum Query - Immutable
+ * https://leetcode.com/problems/range-sum-query-immutable/
+ * Difficulty: Easy
+ *
+ * Given an integer array nums, handle multiple queries of the following type:
+ * - Calculate the sum of the elements of nums between indices left and right inclusive
+ *   where left <= right.
+ *
+ * Implement the NumArray class:
+ * - NumArray(int[] nums) Initializes the object with the integer array nums.
+ * - int sumRange(int left, int right) Returns the sum of the elements of nums between
+ *   indices left and right inclusive (i.e. nums[left] + nums[left + 1] + ... + nums[right]).
+
+ */
+
+/**
+ * @param {number[]} nums
+ */
+var NumArray = function(nums) {
+  this.nums = nums;
+};
+
+/**
+ * @param {number} left
+ * @param {number} right
+ * @return {number}
+ */
+NumArray.prototype.sumRange = function(left, right) {
+  return this.nums.slice(left, right + 1).reduce((sum, n) => sum + n, 0);
+};