some more problems

intersection-of-two-arrays-ii/sol.rs

@@ -0,0 +1,26 @@
+use std::collections::HashMap;
+
+impl Solution {
+    pub fn intersect(nums1: Vec<i32>, nums2: Vec<i32>) -> Vec<i32> {
+        // Get longer & shorter side to optimise memory a little
+        let (longer, shorter) = if nums1.len() > nums2.len() {
+            (nums1.into_iter(), nums2.into_iter())
+        } else {
+            (nums2.into_iter(), nums1.into_iter())
+        };
+        // Get counts of each element of shorter vector
+        let mut counts: HashMap<i32, i32> = shorter
+            .fold(HashMap::new(), |mut counts, n| {
+                counts.insert(n, 1 + *counts.get(&n).unwrap_or(&0));
+                counts
+            });
+        // Filter longer vector using the counts of the elements of the shorter vector
+        longer
+            .filter(|n| {
+                let count = *counts.get(n).unwrap_or(&0);
+                counts.insert(*n, count - 1);
+                count.is_positive()
+            })
+            .collect()
+    }
+}