Add problem 2302: Count Subarrays With Score Less Than K

src/lib.rs

@@ -1709,6 +1709,7 @@ pub mod problem_2294_partition_array_such_that_maximum_difference_is_k;
 pub mod problem_2295_replace_elements_in_an_array;
 pub mod problem_2299_strong_password_checker_ii;
 pub mod problem_2300_successful_pairs_of_spells_and_potions;
+pub mod problem_2302_count_subarrays_with_score_less_than_k;
 
 #[cfg(test)]
 mod test_utilities;

src/problem_2302_count_subarrays_with_score_less_than_k/iterative.rs

@@ -0,0 +1,38 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    pub fn count_subarrays(nums: Vec<i32>, k: i64) -> i64 {
+        let k = k as u64;
+        let mut start = 0;
+        let mut sum = 0;
+
+        (1..).zip(&nums).fold(0, |result, (end, &num)| {
+            sum += u64::from(num as u32);
+
+            while sum * (end - start) >= k {
+                sum -= u64::from(nums[start as usize] as u32);
+                start += 1;
+            }
+
+            result + end - start
+        }) as _
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn count_subarrays(nums: Vec<i32>, k: i64) -> i64 {
+        Self::count_subarrays(nums, k)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_2302_count_subarrays_with_score_less_than_k/mod.rs

@@ -0,0 +1,18 @@
+pub mod iterative;
+
+pub trait Solution {
+    fn count_subarrays(nums: Vec<i32>, k: i64) -> i64;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [((&[2, 1, 4, 3, 5] as &[_], 10), 6), ((&[1, 1, 1], 5), 5)];
+
+        for ((nums, k), expected) in test_cases {
+            assert_eq!(S::count_subarrays(nums.to_vec(), k), expected);
+        }
+    }
+}