rs: add “2215. Find the Difference of Two Arrays”

Signed-off-by: Matej Focko <mfocko@redhat.com>

rs/find-the-difference-of-two-arrays.rs

@@ -0,0 +1,13 @@
+use std::collections::HashSet;
+
+impl Solution {
+    pub fn find_difference(nums1: Vec<i32>, nums2: Vec<i32>) -> Vec<Vec<i32>> {
+        let nums1: HashSet<i32> = nums1.into_iter().collect();
+        let nums2: HashSet<i32> = nums2.into_iter().collect();
+
+        vec![
+            (&nums1 - &nums2).into_iter().collect(),
+            (&nums2 - &nums1).into_iter().collect(),
+        ]
+    }
+}