Add problem 2610: Convert an Array Into a 2D Array With Conditions

Author: EFanZh

src/lib.rs

@@ -1927,6 +1927,7 @@ pub mod problem_2600_k_items_with_the_maximum_sum;
 pub mod problem_2601_prime_subtraction_operation;
 pub mod problem_2602_minimum_operations_to_make_all_array_elements_equal;
 pub mod problem_2609_find_the_longest_balanced_substring_of_a_binary_string;
+pub mod problem_2610_convert_an_array_into_a_2d_array_with_conditions;
 
 #[cfg(test)]
 mod test_utilities;

src/problem_2610_convert_an_array_into_a_2d_array_with_conditions/greedy.rs

@@ -0,0 +1,41 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    pub fn find_matrix(nums: Vec<i32>) -> Vec<Vec<i32>> {
+        let mut counts = vec![0_u8; nums.len()].into_boxed_slice();
+        let mut result = Vec::<Vec<_>>::new();
+
+        for num in nums {
+            let count = &mut counts[num as u32 as usize - 1];
+            let old_count = *count;
+
+            *count += 1;
+
+            if let Some(row) = result.get_mut(usize::from(old_count)) {
+                row.push(num);
+            } else {
+                result.push(vec![num]);
+            }
+        }
+
+        result
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn find_matrix(nums: Vec<i32>) -> Vec<Vec<i32>> {
+        Self::find_matrix(nums)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_2610_convert_an_array_into_a_2d_array_with_conditions/mod.rs

@@ -0,0 +1,36 @@
+pub mod greedy;
+
+pub trait Solution {
+    fn find_matrix(nums: Vec<i32>) -> Vec<Vec<i32>>;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+    use crate::test_utilities;
+    use std::collections::HashSet;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [(&[1, 3, 4, 1, 2, 3, 1] as &[_], 3), (&[1, 2, 3, 4], 1)];
+        let mut buffer = HashSet::new();
+
+        for (nums, expected) in test_cases {
+            let result = S::find_matrix(nums.to_vec());
+
+            assert_eq!(
+                test_utilities::unstable_sorted(result.iter().flatten().copied()),
+                test_utilities::unstable_sorted(nums.iter().copied()),
+            );
+
+            for row in &result {
+                buffer.extend(row.iter().copied());
+
+                assert_eq!(row.len(), buffer.len());
+
+                buffer.clear();
+            }
+
+            assert_eq!(result.len(), expected);
+        }
+    }
+}