Add solution #986

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,067 LeetCode solutions in JavaScript
+# 1,068 LeetCode solutions in JavaScript
 
 [https://leetcode.com/](https://leetcode.com/)
 
@@ -794,6 +794,7 @@
 983|[Minimum Cost For Tickets](./solutions/0983-minimum-cost-for-tickets.js)|Medium|
 984|[String Without AAA or BBB](./solutions/0984-string-without-aaa-or-bbb.js)|Medium|
 985|[Sum of Even Numbers After Queries](./solutions/0985-sum-of-even-numbers-after-queries.js)|Easy|
+986|[Interval List Intersections](./solutions/0986-interval-list-intersections.js)|Medium|
 989|[Add to Array-Form of Integer](./solutions/0989-add-to-array-form-of-integer.js)|Easy|
 994|[Rotting Oranges](./solutions/0994-rotting-oranges.js)|Medium|
 997|[Find the Town Judge](./solutions/0997-find-the-town-judge.js)|Easy|

solutions/0986-interval-list-intersections.js

@@ -0,0 +1,45 @@
+/**
+ * 986. Interval List Intersections
+ * https://leetcode.com/problems/interval-list-intersections/
+ * Difficulty: Medium
+ *
+ * You are given two lists of closed intervals, firstList and secondList, where
+ * firstList[i] = [starti, endi] and secondList[j] = [startj, endj]. Each list of
+ * intervals is pairwise disjoint and in sorted order.
+ *
+ * Return the intersection of these two interval lists.
+ *
+ * A closed interval [a, b] (with a <= b) denotes the set of real numbers x with a <= x <= b.
+ *
+ * The intersection of two closed intervals is a set of real numbers that are either empty
+ * or represented as a closed interval. For example, the intersection of [1, 3] and
+ * [2, 4] is [2, 3].
+ */
+
+/**
+ * @param {number[][]} firstList
+ * @param {number[][]} secondList
+ * @return {number[][]}
+ */
+var intervalIntersection = function(firstList, secondList) {
+  const result = [];
+  let i = 0;
+  let j = 0;
+
+  while (i < firstList.length && j < secondList.length) {
+    const start = Math.max(firstList[i][0], secondList[j][0]);
+    const end = Math.min(firstList[i][1], secondList[j][1]);
+
+    if (start <= end) {
+      result.push([start, end]);
+    }
+
+    if (firstList[i][1] < secondList[j][1]) {
+      i++;
+    } else {
+      j++;
+    }
+  }
+
+  return result;
+};