Add problem 1331: Rank Transform of an Array

src/lib.rs

@@ -541,6 +541,7 @@ pub mod problem_1317_convert_integer_to_the_sum_of_two_no_zero_integers;
 pub mod problem_1323_maximum_69_number;
 pub mod problem_1324_print_words_vertically;
 pub mod problem_1325_delete_leaves_with_a_given_value;
+pub mod problem_1331_rank_transform_of_an_array;
 pub mod problem_1333_filter_restaurants_by_vegan_friendly_price_and_distance;
 pub mod problem_1338_reduce_array_size_to_the_half;
 pub mod problem_1344_angle_between_hands_of_a_clock;

src/problem_1331_rank_transform_of_an_array/mod.rs

@@ -0,0 +1,25 @@
+pub mod sort;
+
+pub trait Solution {
+    fn array_rank_transform(arr: Vec<i32>) -> Vec<i32>;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [
+            (&[40, 10, 20, 30] as &[_], &[4, 1, 2, 3] as &[_]),
+            (&[100, 100, 100], &[1, 1, 1]),
+            (
+                &[37, 12, 28, 9, 100, 56, 80, 5, 12],
+                &[5, 3, 4, 2, 8, 6, 7, 1, 3],
+            ),
+        ];
+
+        for (arr, expected) in test_cases {
+            assert_eq!(S::array_rank_transform(arr.to_vec()), expected);
+        }
+    }
+}

src/problem_1331_rank_transform_of_an_array/sort.rs

@@ -0,0 +1,35 @@
+pub struct Solution;
+
+impl Solution {
+    pub fn array_rank_transform(arr: Vec<i32>) -> Vec<i32> {
+        let mut result = vec![0; arr.len()];
+        let mut nums: Vec<_> = arr.into_iter().zip(0usize..).collect();
+        nums.sort_unstable();
+        let mut prev = None;
+        let mut count = 1;
+        for (num, idx) in nums {
+            if let Some(val) = prev {
+                if val != num {
+                    count += 1;
+                }
+            }
+            result[idx] = count;
+            prev = Some(num);
+        }
+        result
+    }
+}
+
+impl super::Solution for Solution {
+    fn array_rank_transform(arr: Vec<i32>) -> Vec<i32> {
+        Self::array_rank_transform(arr)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}