solves #2215: Find the Difference of Two Arrays in java

Author: anishLearnsToCode

README.md

@@ -721,7 +721,7 @@
 | 2200 | [Find All K-Distant Indices in an Array](https://leetcode.com/problems/find-all-k-distant-indices-in-an-array)                                                         |                                                                               [![Java](assets/java.png)](src/FindAllKDistantIndicesInAnArray.java)                                                                               |                                                                                                                                   |
 | 2206 | [Divide Array Into Equal Pairs](https://leetcode.com/problems/divide-array-into-equal-pairs)                                                                           |                                                                                  [![Java](assets/java.png)](src/DivideArrayIntoEqualPairs.java)                                                                                  |                                                                                                                                   |
 | 2210 | [Count Hills and Valleys in an Array](https://leetcode.com/problems/count-hills-and-valleys-in-an-array)                                                               |                                                                                [![Java](assets/java.png)](src/CountHillsAndValleysInAnArray.java)                                                                                |                                                                                                                                   |
-| 2215 | [Find the Difference of Two Arrays](https://leetcode.com/problems/find-the-difference-of-two-arrays)                                                                   |                                                                                                                                                                                                                                  |                                                                                                                                   |
+| 2215 | [Find the Difference of Two Arrays](https://leetcode.com/problems/find-the-difference-of-two-arrays)                                                                   |                                                                                [![Java](assets/java.png)](src/FindTheDifferenceOfTwoArrays.java)                                                                                 |                                                                                                                                   |
 | 2220 | [Minimum Bit Flips to Convert Number](https://leetcode.com/problems/minimum-bit-flips-to-convert-number)                                                               |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 2224 | [Minimum Number of Operations to Convert Time](https://leetcode.com/problems/minimum-number-of-operations-to-convert-time)                                             |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 2229 | 🔒 [Check if an array is consecutive](https://leetcode.com/problems/check-if-an-array-is-consecutive)                                                                  |                                                                                                                                                                                                                                  |                                                                                                                                   |

src/FindTheDifferenceOfTwoArrays.java

@@ -0,0 +1,35 @@
+// https://leetcode.com/problems/find-the-difference-of-two-arrays
+// T: O(N + M)
+// S: O(N + M)
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+public class FindTheDifferenceOfTwoArrays {
+    public List<List<Integer>> findDifference(int[] nums1, int[] nums2) {
+        final Set<Integer> numbers1 = getSetFrom(nums1);
+        final Set<Integer> numbers2 = getSetFrom(nums2);
+        final List<Integer> distinctElementsInNums1 = difference(numbers1, numbers2);
+        final List<Integer> distinctElementsInNums2 = difference(numbers2, numbers1);
+
+        return List.of(distinctElementsInNums1, distinctElementsInNums2);
+    }
+
+    private Set<Integer> getSetFrom(int[] array) {
+        final Set<Integer> set = new HashSet<>();
+        for (int element : array) {
+            set.add(element);
+        }
+        return set;
+    }
+
+    private List<Integer> difference(Set<Integer> set1, Set<Integer> set2) {
+        final List<Integer> result = new ArrayList<>();
+        for (int element : set1) {
+            if (!set2.contains(element)) result.add(element);
+        }
+        return result;
+    }
+}