Add solution #2570

Author: JoshCrozier

README.md

@@ -681,6 +681,7 @@
 2529|[Maximum Count of Positive Integer and Negative Integer](./2529-maximum-count-of-positive-integer-and-negative-integer.js)|Easy|
 2535|[Difference Between Element Sum and Digit Sum of an Array](./2535-difference-between-element-sum-and-digit-sum-of-an-array.js)|Easy|
 2542|[Maximum Subsequence Score](./2542-maximum-subsequence-score.js)|Medium|
+2570|[Merge Two 2D Arrays by Summing Values](./2570-merge-two-2d-arrays-by-summing-values.js)|Easy|
 2618|[Check if Object Instance of Class](./2618-check-if-object-instance-of-class.js)|Medium|
 2619|[Array Prototype Last](./2619-array-prototype-last.js)|Easy|
 2620|[Counter](./2620-counter.js)|Easy|

solutions/2570-merge-two-2d-arrays-by-summing-values.js

@@ -0,0 +1,34 @@
+/**
+ * 2570. Merge Two 2D Arrays by Summing Values
+ * https://leetcode.com/problems/merge-two-2d-arrays-by-summing-values/
+ * Difficulty: Easy
+ *
+ * You are given two 2D integer arrays nums1 and nums2.
+ * - nums1[i] = [idi, vali] indicate that the number with the id idi has a value equal to vali.
+ * - nums2[i] = [idi, vali] indicate that the number with the id idi has a value equal to vali.
+ *
+ * Each array contains unique ids and is sorted in ascending order by id.
+ *
+ * Merge the two arrays into one array that is sorted in ascending order by id, respecting the
+ * following conditions:
+ * - Only ids that appear in at least one of the two arrays should be included in the resulting
+ *   array.
+ * - Each id should be included only once and its value should be the sum of the values of this
+ *   id in the two arrays. If the id does not exist in one of the two arrays, then assume its
+ *   value in that array to be 0.
+ *
+ * Return the resulting array. The returned array must be sorted in ascending order by id.
+ */
+
+/**
+ * @param {number[][]} nums1
+ * @param {number[][]} nums2
+ * @return {number[][]}
+ */
+var mergeArrays = function(nums1, nums2) {
+  const map = new Map(nums1);
+  for (const [key, value] of nums2) {
+    map.set(key, (map.get(key) ?? 0) + value);
+  }
+  return [...map].sort((a, b) => a[0] - b[0]);
+};