Add problem 2341: Maximum Number of Pairs in Array

src/lib.rs

@@ -1736,6 +1736,7 @@ pub mod problem_2331_evaluate_boolean_binary_tree;
 pub mod problem_2335_minimum_amount_of_time_to_fill_cups;
 pub mod problem_2336_smallest_number_in_infinite_set;
 pub mod problem_2337_move_pieces_to_obtain_a_string;
+pub mod problem_2341_maximum_number_of_pairs_in_array;
 
 #[cfg(test)]
 mod test_utilities;

src/problem_2341_maximum_number_of_pairs_in_array/iterative.rs

@@ -0,0 +1,36 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    pub fn number_of_pairs(nums: Vec<i32>) -> Vec<i32> {
+        let n = nums.len() as u8;
+        let mut seen = 0_u128;
+        let mut pairs = 0;
+
+        for num in nums {
+            let probe = 1 << (num as u8);
+
+            pairs += u8::from((seen & probe) != 0);
+            seen ^= probe;
+        }
+
+        vec![i32::from(pairs), i32::from(n - pairs * 2)]
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn number_of_pairs(nums: Vec<i32>) -> Vec<i32> {
+        Self::number_of_pairs(nums)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_2341_maximum_number_of_pairs_in_array/mod.rs

@@ -0,0 +1,22 @@
+pub mod iterative;
+
+pub trait Solution {
+    fn number_of_pairs(nums: Vec<i32>) -> Vec<i32>;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [
+            (&[1, 3, 2, 1, 3, 2, 2] as &[_], [3, 1]),
+            (&[1, 1], [1, 0]),
+            (&[0], [0, 1]),
+        ];
+
+        for (nums, expected) in test_cases {
+            assert_eq!(S::number_of_pairs(nums.to_vec()), expected);
+        }
+    }
+}