solves #2570: Merge Two 2D Arrays by Summing Values in java

Author: anishLearnsToCode

README.md

@@ -802,7 +802,7 @@
 | 2558 | [Take Gifts From the Richest Pile](https://leetcode.com/problems/take-gifts-from-the-richest-pile)                                                                     |                                                                                 [![Java](assets/java.png)](src/TakeGiftsFromTheRichestPile.java)                                                                                 |                                                                                                                                   |
 | 2562 | [Find the Array Concatenation Value](https://leetcode.com/problems/find-the-array-concatenation-value)                                                                 |                                                                               [![Java](assets/java.png)](src/FindTheArrayConcatenationValue.java)                                                                                |                                                                                                                                   |
 | 2566 | [Maximum Difference by Remapping a Digit](https://leetcode.com/problems/maximum-difference-by-remapping-a-digit)                                                       |                                                                             [![Java](assets/java.png)](src/MaximumDifferenceByRemappingADigit.java)                                                                              |                                                                                                                                   |
-| 2570 | [Merge Two 2D Arrays by Summing Values](https://leetcode.com/problems/merge-two-2d-arrays-by-summing-values)                                                           |                                                                                                                                                                                                                                  |                                                                                                                                   |
+| 2570 | [Merge Two 2D Arrays by Summing Values](https://leetcode.com/problems/merge-two-2d-arrays-by-summing-values)                                                           |                                                                               [![Java](assets/java.png)](src/MergeTwo2DArraysBySummingValues.java)                                                                               |                                                                                                                                   |
 | 2574 | [Left and Right Sum Differences](https://leetcode.com/problems/left-and-right-sum-differences)                                                                         |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 2578 | [Split With Minimum Sum](https://leetcode.com/problems/split-with-minimum-sum)                                                                                         |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 2582 | [Pass the Pillow](https://leetcode.com/problems/pass-the-pillow)                                                                                                       |                                                                                                                                                                                                                                  |                                                                                                                                   |

src/MergeTwo2DArraysBySummingValues.java

@@ -0,0 +1,43 @@
+// https://leetcode.com/problems/merge-two-2d-arrays-by-summing-values
+// T: O(N + M)
+// S: O(N + M)
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class MergeTwo2DArraysBySummingValues {
+    public int[][] mergeArrays(int[][] array1, int[][] array2) {
+        final List<int[]> result = new ArrayList<>();
+        int i = 0, j = 0;
+        while (i < array1.length && j < array2.length) {
+            if (array1[i][0] == array2[j][0]) {
+                result.add(new int[] {array1[i][0], array1[i][1] + array2[j][1]});
+                i++;
+                j++;
+            } else if (array1[i][0] < array2[j][0]) {
+                result.add(array1[i++]);
+            } else {
+                result.add(array2[j++]);
+            }
+        }
+
+        while (i < array1.length) {
+            result.add(array1[i++]);
+        }
+
+        while (j < array2.length) {
+            result.add(array2[j++]);
+        }
+
+        return toArray(result);
+    }
+
+    private int[][] toArray(List<int[]> list) {
+        final int[][] array = new int[list.size()][2];
+        int k = 0;
+        for (int[] slice : list) {
+            array[k++] = slice;
+        }
+        return array;
+    }
+}