Add solution #898

Author: JoshCrozier

README.md

@@ -708,6 +708,7 @@
 895|[Maximum Frequency Stack](./0895-maximum-frequency-stack.js)|Hard|
 896|[Monotonic Array](./0896-monotonic-array.js)|Easy|
 897|[Increasing Order Search Tree](./0897-increasing-order-search-tree.js)|Easy|
+898|[Bitwise ORs of Subarrays](./0898-bitwise-ors-of-subarrays.js)|Medium|
 901|[Online Stock Span](./0901-online-stock-span.js)|Medium|
 905|[Sort Array By Parity](./0905-sort-array-by-parity.js)|Easy|
 909|[Snakes and Ladders](./0909-snakes-and-ladders.js)|Medium|

solutions/0898-bitwise-ors-of-subarrays.js

@@ -0,0 +1,33 @@
+/**
+ * 898. Bitwise ORs of Subarrays
+ * https://leetcode.com/problems/bitwise-ors-of-subarrays/
+ * Difficulty: Medium
+ *
+ * Given an integer array arr, return the number of distinct bitwise ORs of all the non-empty
+ * subarrays of arr.
+ *
+ * The bitwise OR of a subarray is the bitwise OR of each integer in the subarray. The bitwise
+ * OR of a subarray of one integer is that integer.
+ *
+ * A subarray is a contiguous non-empty sequence of elements within an array.
+ */
+
+/**
+ * @param {number[]} arr
+ * @return {number}
+ */
+var subarrayBitwiseORs = function(arr) {
+  const results = new Set();
+  let previous = new Set();
+
+  for (const num of arr) {
+    const current = new Set([num]);
+    for (const prev of previous) {
+      current.add(prev | num);
+    }
+    previous = current;
+    previous.forEach(val => results.add(val));
+  }
+
+  return results.size;
+};